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ANAT216 - Block #2 Review
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188
Anatomy
Undergraduate 2
03/13/2011

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Term
Structural Components of the Lymph System
Definition
Lymph Vessels (capillaries, vessels, trunks, ducts)
Lymph Tissues & Organs (Nodes, Spleen, Thymus)
Term
Difference between ISF and lymph
Definition
ISF = fluid that exists in interstitium
Lymph = ISF that has been taken into a lymph vessel
Term
Lymph always flows...
Definition
Towards the heart (lymphatics form a one-way vessel system)
Term
Lymph capillaries are found everywhere except...
Definition
Bone, bone marrow, cartilage, CNS
Term
What makes lymphatic capillaries so permeable?
Definition
Overlapped endothelial cells in wall (don't have tight junctions), which can form easily opened flaps.
Bundles of filaments anchor endothelium to CT; when ISF volume (pressure) increases, the flaps allow for the ONE WAY opening of the flaps between endothelial cells for the lymph to enter the vessels; filaments also prevent vessel collapse
Term
Lymph Collecting Vessels
Definition
Similar to veins in structure, but have MORE valves; this is due to the decreased pressure in the lymphatic system (no central pump)
To pump lymph through the vessels, the major reliance is on the skeletal muscle pump (contraction of surrounding muscles pushes lymph towards heart)
Term
Superficial and deep lymphatic collecting vessels merge to form...
Definition
Lymphatic trunks
Term
Types of Lymphatic Trunks in the Body
Definition
Lumbar, Intestinal, Bronchomediastinal, Jugular, Subclavian
All are paired trunks; similar to veins in structure
Term
Lymphatic Ducts
Definition
2 exist in the body: R lymphatic duct, and thoracic duct

Receive lymph from respective lymphatic trunks
Term
Right Lymphatic Duct
Definition
Collects lymph from the R side of the body above the diaphragm
Drains into the junction of the R subclavian and R internal jugular veins
Term
Thoracic Duct
Definition
Begins at the level of L1-L2 @ CISTERNA CHYLI (receives lymph from intestinal and lumbar trunks); travels upwards and empties into the L subclavian vein before it joins with the L internal jugular vein

Collects lymph from both sides below the diaphragm and the L side above the diaphragm
Term
Two main types of lymphoid cells:
Definition
Macrophages - differentiated (mature) monocytes; involved in the phagocytosis of pathogens & debris
Lymphocytes - agranular leukocytes involved in cell mediated and antibody mediated immunity
Term
Lymphocytes
Definition
T cells (80%), B cells (15%), NK cells (5%)
Term
T Lymphocytes
Definition
Function to manage immune response; some can directly attack antigen; responsible for CELL mediated immunity
Cytotoxic T cell - warriors; directly attack and destroy antigens
Helper T / Suppressor T cells - assist in coordination of immune response; control B cell differentiation; suppressor T can shut down cytotoxic T cells ("off switch")
Memory T cell - remembers antigen; if reintroduced to body, 1st to respond
Term
B lymphocytes
Definition
Protect body by ability to produce antibodies; responsible for ANTIBODY mediated immunity
B cells activated by exposure to antigen, can differentiate into PLASMA cell
Helper T - promote differentiation of B cells
Suppressor T - inhibit differentiation of B cells
Memory B cells - same function as memory T
Term
NK cells
Definition
Can directly attack antigens; do not need to be stimulated or activated to function; "immunoserveillance cells"
Term
Variations of Lymph Tissue
Definition
Diffuse Lymph Tissue - scattered elements of reticular CT; found in mucous membranes & lymph organs
Lymph Follicles/Nodules - solid accumulation of reticular CT; germinal centers contain mature differentiating B cells (into plasma cells)
Term
Locations of Lymph Nodules/Follicles
Definition
Digestive tract (GALT)
In the pharynx and oral cavity as TONSILS (pharyngeal, palatine, lingual)
Beneath mucosa of Ileum (Peyer's patches)
Appendix
Term
Lymph Organs
Definition
Composed of diffuse lymph tissue and/or lymph follicles AND enclosed by a capsule of dense CT

Examples - lymph nodes, thymus, spleen
Term
Lymph Nodes
Definition
Function is to filter lymph as it passes through circulation and activate immune response
Bean-shaped; 1mm-2.5cm in length

3 main locations - cervical, axillary, inguinal
Term
Capsule Structure of Lymph Nodes
Definition
Nodes are surrounded by fibrous CT capsule; portions project inwards (TRABECULAE) to separate the cortex of the node into smaller areas
Term
Cortex of Lymph Nodes
Definition
Divided by trabeculae of cortex; foundation of diffuse lymph tissue and is scattered with lymph follicles (containing differentiating B cells @ germinal centers)
Term
Deep Cortex of Lymph Nodes
Definition
Found in between cortex & medulla; location of T cells in the nodes
Term
Medulla of Lymph Nodes
Definition
Primarily made of MEDULLARY CORDS (extensions of diffuse lymph tissue from cortex)

Find B cells + plasma cells
Term
Sinuses of Lymph Nodes
Definition
Afferent lymphatics deposit lymph into the subcapsular sinus; lymph passes from subcapsular sinus, into trabecular sinuses, and finally into medullary sinuses
From here it drains into the hilus of the node, where it is taken away by efferent lymphatics
Term
Path of lymph travelling through a lymph node
Definition
Enters @ subcapsular sinus from afferent lymphatics; dendritic cells in diffuse lymph tissue trap pathogens and debris until they can be removed by macrophages; lymph continues through trabecular and then medullary sinuses before being emptied into the hilus and carried away by efferent lymphatics
Term
Thymus
Definition
Lymph organ located in the upper mediastinum; anterior to the great vessels of the heart
Size peaks during adolescence, then is gradually replaced by fatty CT
Function is to secrete hormones to stimulate maturation of stem cells into immunocompetent T cells
Term
Structure of the Thymus
Definition
Divided into 2 lobes; lobes are subdivided into lobules by septae
Contains a cortex and a medulla
Foundation is NOT diffuse lymph tissue; made of EPITHELIAL RETICULAR CELLS
Term
Cortex of Thymus
Definition
Stem cells migrate here from the bone marrow; only some mature into T cells
Cortex is impermeable to blood (blood-thymus barrier) to prevent early exposure of antigens to immature T cells
Mature T cells are believed to enter circulation at the cortex-medulla interface
T cells in the cortex are NOT involved in the immune response
Term
Medulla of Thymus
Definition
Also based on epithelial reticular cells; clusters of these cells = Hassal's corpuscles (unknown function)
Also believed that mature T cells will migrate here following differentiation
Term
Spleen
Definition
Largest lymph organ in the body; L side of abdomen, inferior the diaphram between the stomach and the kidney
Covered by a dense CT capsule, but trabeculae DO NOT divide the spleen into lobes/lobules; no distinct cortex or medulla
Functions to filter and store blood, and activate the immune system
Term
Surfaces of the Spleen
Definition
Diaphragmatic - smooth superior surface contoured to diaphragm
Visceral - medial surface; indentation for stomach and kidney (gastric and renal areas); knuckles represent the gastric area
Hilum of the spleen exists at the border between the gastric and visceral areas (entrance/exist for splenic vein and artery); note - splenic artery is highly coiled, splenic vein is not
Term
Histology of the Spleen
Definition
White Pulp - contains lymphatic follicles and activates immune system
Red Pulp - filters and stores blood
Term
White Pulp
Definition
Consists of lymphatic nodules formed around a central artery
Germinal centers contain plasma, B, and T cells
Term
Functional Regions of the Respiratory System and their Functions
Definition
Conducting Portion - from nasal cavity to terminal bronchioles; functions as a conduit for air, also conditions air (warm, humidify, filter)
Respiratory Portion - from respiratory bronchioles to alveoli; site of gas exchange
Term
RTE
Definition
Pseudostratified ciliated columnar epithelium w/ goblet cells; conditions inspired and expired air; only found in conducting portion
Term
Nose and Nasal Cavity
Definition
Primary pathway for air entering system
Nasal cavity divided into 2 by a nasal septum - anterior = hyaline cartilage; posterior = bone (ethmoid + vomer)
Term
Boundaries of the Nasal Cavity
Definition
Roof = ethmoid, sphenoid, frontal bones
Floor = palate
Walls = maxillary bones
Term
Regions of the Nasal Cavity
Definition
Vestibule - portion directly behind external nares
Fossae - includes the superior, middle, inferior nasal conchae
Term
Nasal Conchae
Definition
Superior, middle, inferior
Exist to condition the air; structure allows them to act as turbines to mix the air and condition thoroughly
Normal RTE in inferior & middle; in superior RTE, NO goblet cells, instead contains olfactory epithelium involved in smell
Term
Process of Air Conditioning by RTE
Definition
Warm - heat from underlying BVs warms RTE, which transfers heat to inspired air
Humidify - lamina propria and serous membranes secrete fluid
Filter - cilia and mucous in vestibule and fossae
Term
Paranasal Sinuses
Definition
Ethmoid, Sphenoid, Frontal, Maxillary
Spaces in bones ALL connected by narrow passage to nasal cavity
Lined with RTE (aid in conditioning)
Term
Pharynx
Definition
Connects nasal & oral cavities to larynx & esophagus
Functions for food & air
Wall is made of skeletal muscle (pharyngeal constrictors)
3 regions - naso, oro, laryngo
Term
Nasopharynx
Definition
From posterior nasal cavity to level of soft palate
Lined with RTE (functions only for air)
Contains opening to Eustachian tubes in lateral walls, and pharyngeal tonsils in posterior wall
Term
Oropharynx
Definition
From the level of the soft palate to the base of the tongue (epiglottis)
Lined with stratified squamous epithelium; used for food and air
Term
Laryngopharynx
Definition
From the base of tongue (epiglottis) to the beginning of the larynx
Lined with stratified squamous epithelium; food + air
Continuous with the esophagus
Term
Larynx
Definition
Functions to connect the laryngopharynx to the trachea, and produces sound; made of 9 cartilages (thyroid, cricoid, epiglottis, corniculate, cuneiform, arytenoid)
Larynx moves UP while swallowing so epiglottis covers opening (prevents food from entering)
Term
What cartilages form the body of the larynx?
Definition
Thyroid cartilage, Cricoid cartilage, Epiglottis
Term
What cartilage anchors the vocal ligaments?
Definition
The arytenoid cartilage (vocal ligaments connect arytenoid and thyroid cartilages)
Term
True Vocal Cords
Definition
Inferior to false vocal cords; includes vocal ligament + fold; produce sound
Space between folds = GLOTTIS
Term
False Vocal Cords
Definition
Located superior to true vocal cords; consists of vestibular ligament + fold
Term
Epithelium of the larynx?
Definition
RTE
Term
Trachea
Definition
Aka Windpipe; connects larynx to the mediastinum
Divides into primary bronchi at carina at level of T4-T5
3 main histological layers - mucosa, submucosa, adventitia
Term
Histology of the Trachea
Definition
Mucosa = RTE + lamina propria
Submucosa = dense irreg CT + mucous glands
Adventitia = CT internally reinfored by C-shaped rings of hyaline cartilage
Trachealis = layer of smooth muscle at posterior trachea; connects hyaline rings and allows for expansion or compression of the trachea
Term
Primary Bronchi
Definition
Also known as EXTRApulmonary bronchi (outside lungs); 1 goes to each lun
R primary bronchus - wider, shorter, more vertical (more food gets stuck here)
Bronchi enter lungs at hilus (roote of lung) on oblique angle
Term
Pleural Membranes
Definition
Parietal Pleura - lines inside of thoracic wall (lateral mediastinum) and superior diaphragm
Visceral Pleura - directly lines the lungs
Both are serous membranes and secrete pleural fluid to lubricate lungs
Term
Surfaces/Features of the Lungs
Definition
Apex (Cupola) - anterior portion of lung that projects into the neck area
Diaphragmatic (Base) - sits on diaphragm
Costal - anterior, posterior, lateral surfaces
Medial - hilus (root) of lung; L lung contains cardiac notch on medial surface
Term
Differences between R and L lung:
Definition
R lung - shorter than L lung due to liver pushing up on diaphragm; 3 lobes, 2 fissures (horizontal = superior from middle; oblique = superior & middle from inferior)
L lung - smaller than R lung due to presence of heart and great vessels; 2 lobes, 1 fissure (oblique)
Term
Segmentation of the Lobes
Definition
Lobes are broken down into bronchopulmonary segments; each is separate identity (individual vessels, nerves, lymphatics)
Segments are further subdivided by CT to form pulmonary lobules (each is individual as well)

Can remove an individual lobule or segment without interfering with the structural or functional integrity of the lung
Term
Bronchial Tree
Definition
Primary Bronchi - 1 to each lung
Secondary (Lobar) Bronchi - 1 to each lobe (3 to right, 2 to left)
Tertiary (Segmental Bronchi) - 1 per bronchopulmonary segment, 10 to each lung (R = 3, 2, 5; L = 5, 5)
Terminal Bronchioles - supply individual pulmonary lobules
Term
Histological Transitions of Bronchial Tree
Definition
- As the bronchi subdivide, the amount of cartilage decreases; NO cartilage in terminal bronchioles
- Epithelium Transitions - RTE -> ciliated simple columnar -> ciliated simple cuboidal -> simple cuboidal (in bronchioles)
- Relative amount of smooth muscle in walls increases as segmentation increases
Term
Respiratory Portion of the Lungs
Definition
Respiratory Bronchioles - cuboidal; branch from terminal bronchioles; contain increasing amounts of alveoli
Alveolar Ducts - contain only alveoli in their walls; end in blind-ended alveolar sacs
Term
Alveoli Features
Definition
Site of gas exchange in the lungs
Type I cells - simple squamous epithelium; endothelium
Type II cells - cuboidal surfactant cells; lamellar bodies in type II cells produce surfactant
Alveolar Pore - holes in alveoli to connect adjacent ones which serve to equalize air pressure
Interalveolar Septum - consists of the respiratory membrane as well as interstitium
Term
Respiratory membrane = ?
Definition
Type I cell (endothelium) + lamina propria of alveoli and capillary + capillary endothelium

This is the membrane that air must cross to diffuse into the capillaries
Term
What are the most important muscles of respiration?
Definition
Diaphragm + external/internal intercostals
Term
Diaphragm (mechanics of breathing)
Definition
Contract = increase volume of thoracic cavity (inspire)
Relax = decrease volume of thoracic cavity (exhale)
Term
Intercostals (mechanics)
Definition
External = contract to elevate the rib cage to increase volume during inspiration
Internal = contract to depress ribcage which decreases volume during expiration
Term
Eupnea vs Hypnea
Definition
Eupnea = quite breathing; inspiratory muscles are used, but expiration occurs passively
Hypnea = forced breathing; involves active inspiratory and expiratory movements
Term
Types of Eupnea
Definition
Diaphragmatic Breathing - deep breathing; uses mainly the diaphragm
Costal breathing - shallow breathing; uses mainly the intercostals
Term
Regulatory Centers for Respiration
Definition
Respiratory Rhythmicity Center - located in the medulla; sets pace and depth; DRG = inspiration (always functioning); VRG = only functions during hyperpnea (forced breathing)
Apneustic & Pneumotaxic Centers - in pons; regulate output of rhythmicity center
Term
Epithelium of Oral Cavity?
Definition
Oral Mucosa = strat. squamous epithelium (non-keratinized)
Term
Components of the Oral Cavity:
Definition
Vestibule - space located between lips & cheeks, and gums & teeth; initial location of food
Oral Cavity Proper - main component of the mouth; lateral walls = alveolar arches; roof = palate; floor = tongue
Term
Palate
Definition
Hard Palate = anterior portion (bony)
Soft Palate = posterior portion (skeletal muscle); uvula is the extension of distal soft palate (used in pronunciation)

During swallowing, soft palate elevates to close off nasopharynx
Term
Fauces (Anterior + Posterior)
Definition
Anterior = Palatoglossal Arch; from palate to tongue
Posterior = Palatopharyngeal Arche; from palate to pharynx

Palatine tonsils exist in between the anterior and posterior arches
Term
What connects the tongue to the floor of the mouth?
Definition
Lingual Frennulum
Term
Intrinsic Muscles of the Tongue
Definition
Have origins and insertions on the tongue; involved in altering the shape of the tongue (e.g. tongue-roller)
Run in 3 directions - longitudinal, transverse, vertical
Innervated by CN XII (hypoglossal)
Term
Extrinsic Muscles of the Tongue
Definition
3 main muscles - Styloglossus, Hyloglossus, Genioglossus
Function in the main movements of the tongue
All innervated by CN XII
Term
Genioglossus
Definition
o = posterior mangible; i = tip of tongue
Paired muscle; each muscle pulls the tongue to the opposite side (R genioglossus moves tongue to the left, and vice versa)
If CN XII has a lesion, the direction the tongue points to is the side of the lesion (e.g. lesion of L CN XII, tongue will point to left because only the R genioglossus can contract)
Term
Styloglossus
Definition
o = styloid process of temporal bone; i = tongue
Pulls tongue upwards, pulls tongue inwards
Term
Hyloglossus
Definition
o = hyoid bone; i = tongue
Pulls tongue downwards, pulls tongue inwards
Term
Divisions of the Tongue
Definition
Anterior 2/3 - BODY of the tongue; this is the mobile portion of the tongue
Posterior 1/3 - ROOT of the tongue; attached to hyoid bone; lingual tonsils are submucosal to the root

Body and root of tongue are separated by a fibrous septum
Term
Papillae of the Tongue
Definition
Projections of epithelium of the tongue; only on anterior 2/3 (body)
3 types - filliform, fungiform, circumvallate
Term
Filiform Papillae
Definition
Located on distal body of tongue; elongated; composed of stratified squamous epithelium (keratinized)
Term
Fungiform papillae
Definition
In the "middle" of the tongue; pinkish shaped mushroom looking projections; contain dorsal taste buds
Term
Circumvallate Papillae
Definition
Located at the junction of the body & root of the tongue; only have 10-12; taste buds located in the wall of the trough
Term
Taste Bud Structure
Definition
Taste buds contain approximately 40 taste cells (gustatory cells)
Gustatory cells have microvilli which project through taste pore to absorb food particles and send signals back to the CNS
Basal cells (produce new taste cells); supportive (transitional cells) also exist
Term
Types of Taste
Definition
Sweet, sour, bitter, salty, umami (savoury)

Also have discovered taste receptors for water
Term
Salivary Glands
Definition
Minor glands - cheeks, tongue, lips
Major glands - parotid, submandibular, sublingual
Term
Parotid Glands
Definition
Located anterior to the ears; parotid duct (Stenson's) travels anterior to the masseter to empty into the vestibule of the mouth opposite the 2nd upper molar
Secretes serous fluid (serous acini) as well as amylase
Term
Submandibular Glands
Definition
Located under the mandible; submandibular (Wharton's) duct crosses over mylohyoid to empty into the floor of the mouth near the lingual frenulum
Secretes serous fluid + mucous (serous and mucous acini)
Term
Sublingual Glands
Definition
Paired glands located under the tongue; 10-12 sublingual ducts release mucous secretions into the floor of the mouth (mucous acini)
Term
What is the functional unit of a salivary gland?
Definition
Acinus (either mucous or serous)
Term
Deciduous Teeth
Definition
20 in total
2 incisors, 1 canine (cuspid), 2 molars / half jaw
Term
Permanent Teeth
Definition
32 in total
2 incisors, 1 canine (cuspid), 2 premolars (bicuspid), 3 molars / half jaw
Term
Eruption Times for Deciduous Teeth
Definition
6 months = 1st incisor
12 months = 1st molar
24 months = all teeth
Term
Eruption Times for Permanent Teeth
Definition
6 years = 1st incisor and 1st molar
12 years = 2nd molar & all anterior to 2nd molar
24 years = wisdom teeth (3rd molar)
Term
Parts of a tooth
Definition
Crown = visible portion of tooth above gingiva
Root = part of tooth in alveolus
Neck = junction of crown & root (@ gingiva)
Dentin = calcified portion of the tooth
Enamel = hardest biological material; irreplaceable; outer layer of tooth
Term
Alveolus
Definition
socket; alveolar bone teeth sit in

If a tooth is removed, the alveolus (alveolar bone) begins to recede
Term
Gingiva
Definition
"Gums"; Stratified squamous epithelium that covers the alveolus
Term
Pulp Cavity
Definition
Loose CT deep to dentin; location of arteries, veins, nerves
Term
Apical Foramen
Definition
Entrance of vessels and nerves into root canal; root canal directs vessels and nerves to pulp cavity
Term
What is the narrowest portion of the pharynx?
Definition
Laryngopharyx; this is because the larynx pushes into its anterior wall, compressing it
Term
Pharyngeal Constrictor Muscles
Definition
Paired muscles; superior, middle, lower; skeletal muscle
Function to narrow the pharynx during swallowing which pushes the food towards the esophagus
Involved in the gag reflex
Innervated by CN IX (glossopharyngeal)
Term
Phases of Swallowing
Definition
Buccal Phase (Voluntary) - food enters the mouth; teeth and tongue compress food and tongue pushes bolus towards the oropharynx
Pharyngeal (Involuntary) - soft palate elevates to prevent food from entering nasopharynx; pharyngeal constrictors contract to propel food to esophagus; larynx elevates so that epiglottis covers its opening
Esophageal (Involuntary) - muscles of esophagus propel food towards stomach via peristaltic waves
Term
What is unique about the epiglottis/larynx during infancy?
Definition
During infancy, the epiglottis is raised so it is visible in the oropharynx; during breastfeeding, the larynx elevates and connects to the nasopharynx so that the baby can breathe and swallow at the same time
Term
Histology of the GI Wall
Definition
Mucosa - surface epithelium (variable); lamina propria (loose CT); muscularis mucosa (smooth muscle)
Submucosa - dense irregular CT containing vessels, lymphatics, and glands; contains submucosal (Meissner's) plexus which innervates structures in mucosa and submucosa
Muscularis Externa - inner circular muscle layer, outer longitudinal muscle layer; between layers there is the myenteric (Auerbach's) plexus which innervates the layers
Adventitia or Serosa - adventitia = only CT; serosa = lined with peritoneum
Term
Peritoneum
Definition
Serous membrane secreting serous fluid (peritoneal fluid)
Visceral Peritoneum - lines the organs
Parietal Peritoneum - lines the abdominal wall
Mesentery - double layer of peritoneum
Term
Intra vs. Retro Peritoneal
Definition
Intraperitoneal - organ is completely covered in peritoneum
Retroperitoneal - organ is covered only anteriorly by peritoneum; posterior is against the abdominal wall
Term
Esophagus
Definition
Connects pharynx to the stomach; begins in neck, ends in abdominal cavity
In upper mediastinum, it is posterior to the trachea; in the lower mediastinum it is posterior to the L atrium.
Term
Esophageal Hiatus
Definition
Located at the level of T10; end-point of esophagus in the thoracic cavity
Located as a space in the diaphragm that the esophagus passes through to enter the abdominal cavity
Clinical Case -> Hiatus Hernia - when part of the stomach herniates through the hiatus
Term
Histology of the Esophagus
Definition
Mucosa - stratified squamous epithelium + lamina propria + muscularis mucosa
Submucosa - dense irregular CT, mucous glands + submucosal (Meissner's) plexus
Muscularis Externa - inner circular, outer longitudinal; upper 1/3 = skeletal; middle 1/3 = skeletal and smooth; lower 1/3 = smooth
Adventitia - CT only; last 1-2 cm in abdominal cavity does have serosa (retroperitoneal)
Term
Upper Esophageal Sphincter
Definition
Near junction of pharynx and esophagus; not a definitive sphincter; remains closed until swallowing, then relaxes
Involved in eruptation and sound production
Term
Lower Esophageal Sphincter
Definition
Located at the end of the thoracic esophagus (above hiatus); prevents reflux from stomach from entering the esophagus
Term
Stomach Regions
Definition
Cardia - where esophagus joins to stomach
Fundus - elevated portion above cardia; sits in L dome of diaphragm and is usually filled with air
Body - main portion of stomach
Pylorus - distal portion which joins w/ duodenum
Term
Stomach Curvature
Definition
Greater curvature = lateral
Lesser curvature = medial
Term
Mesentery of the Stomach
Definition
Greater Omentum - dorsal mesentery which connects the stomach to the posterior abdominal wall
Lesser Omentum - part of ventral mesentery that connects the stomach and the liver
Term
Mucosa of the Stomach (Rugae + Gastric Pits)
Definition
Ridges in mucosa = RUGAE; disappear when stomach fills
Stomach mucosa is lined with simple columnar epithelium located in the gastric pits of the stomach; neck cells in gastric pits replace absorptive cells)
Term
Mucosa of the Stomach (Gastric Glands)
Definition
Parietal Cells - large & round w/ a central nucleus; secrete HCl and intrinsic factor (for vitamin B12 uptake)
Chief Cells - cuboidal cells with basal nucleus; secrete pepsinogen (pepsinogen becomes pepsin due to acidity of HCl)
Enteroendocrine Cells (G cells) - secrete gastrin (gastrin stimulates parietal and chief cells)
Term
Muscularis Externa of the Stomach
Definition
3 layers of smooth muscle in the stomach (aid in mixing of stomach contents):
Inner oblique layer
Middle circular layer
Outer longitudinal layer

At pyloric sphincter, middle circular layer thickens to form sphincter
Term
Which layers of the GI wall does the stomach possess (histology)
Definition
Mucosa, Submucosa, Muscularis Externa, Serosa (stomach is intraperitoneal)
Term
Blood Supply / Drainage of the Stomach
Definition
The stomach is supplied by the 3 branches of the celiac trunk - splenic, L gastric, common hepatic

Corresponding veins responsible for drainage into PORTAL VEIN
Term
Parts of the Small Intestine
Definition
Duodenum (proximal), Jejunum (middle), Ileum (distal)
Term
Duodenum
Definition
Proximal region of small intestine; connects to pylorus of stomach at pyloric sphincter; shortest portion = 25 cm
Receives common bile duct and pancreatic duct at duodenal ampulla, which empties into the duodenal papilla
Duodenum is RETROPERITONEAL
Term
Jejunum & Ileum
Definition
J = 2.5 m; I = 3.5 m; both are covered by a fan-shaped mesentery, and are therefore INTRAPERITONEAL -> dorsal mesentery (mesentery proper) suspends jejunum and ileum to the posterior abdominal wall
Term
Blood Supply / Drainage of the Small Intestine
Definition
Receives blood from the superior mesenteric artery (branch from abdominal aorta)
Blood drains into superior mesenteric veins, which connect to the hepatic portal vein
Term
Mucosa of the Small Intestine
Definition
Plicae Circularis - permanent transverse folds in mucosa
Villi - finger-like projections of mucosa of the small intestine; covered with microvilli (brush border) to further increase the surface area
Villi are lined with absorptive cells (simple columnar epithelium) lined with microvilli
Crypts of Lieberkuhn - deep projections in between villi
Lamina Propria - forms a CORE for each villus, containing its blood supply; blood capillaries and lymphatic capillaries (lacteals; for fat digestion)
In jejunum - isolated lymphatic nodules in lamina propria
In ileum - aggregated lymphatic nodules (Peyer's Patches)
Term
Crypts of Lieberkuhn (Small Intestine)
Definition
Intestinal glands projecting deep into intestinal walls located in between villi
Contain absorptive & goblet cells (like villi)
Paneth Cells - at base of crypt; secrete lysozyme (anti-bacterial)
Enteroendocrine Cells - @ base; secrete secretin & CCK (control gallbladder and pancreatic secretions)
Stem Cells - continuous regeneration of cells
Term
Submucosa of Small Intestine
Definition
In duodenum, contains duodenal (Brunner's) glands that secrete alkaline mucous; protective measures against acidic stomach contents
Term
Meckel's Diverticulum
Definition
Projection of the ileum; most common congenital anomaly of the small intestine; 2% of population have it; 2 " long; basically looks like "appendix" on ileum
Term
Regions of the Large Intestine
Definition
3 main regions - Cecum, Colon (Ascending, Transverse, Descending, Sigmoid), Rectum
Total large intestine = 1.5 m long
Term
Cecum
Definition
Connects w/ ileum @ ileocecal valve
Vermiform Appendix - projection from cecum; contains many lymph nodules in wall; can be retrocecal (behind cecum) or pelvic (in pelvis)
Term
Distinctive Features of Colon
Definition
Teniae Coli - 3 bands of longitudinal muscle
Haustra - "saculations"; gives colon segmented appearance
Epiplotic Appendages - sacs of fat in peritoneum
Term
What is the main function of the large intestine?
Definition
Reabsorb water and electrolytes from feces
Term
Ascending Colon
Definition
From cecum -> upper R section of abdominal cavity; RETROPERITONEAL
Turns @ R colic (hepatic) flexure
Term
Transverse Colon
Definition
Runs transversely from liver to spleen
INTRAPERITONEAL - suspended by transverse mesocolon
Turns to become descending colon @ L colic (splenic) flexure
Term
Descending Colon
Definition
Travels downwards along the L side of the abdominal cavity; RETROPERITONEAL
Term
Sigmoid Colon
Definition
Terminal portion of colon; INTRAPERITONEAL -> suspended by sigmoid mesocolon
Term
Rectum
Definition
Storage area for feces; S-shaped in humans with 3 transverse rectal folds (aid in storage of feces)
Terminal portion = anal canal; anal columns are connected at the pectinate line by anal valves
2 sphincters (internal, external)
Term
Anal Sphincters
Definition
Internal - thickened circular layer of muscularis externa (smooth muscle)
External - skeletal muscle (voluntary)
Term
Blood Supply / Drainage of the Large Intestine
Definition
Superior Mesenteric Artery = Cecum, Ascending and Transverse Colon (R side of large intestine)
Inferior Mesenteric Artery = Descending & Sigmoid Colon, Rectum (L side of large intestine)

Corresponding veins drain venous blood into hepatic portal vein
Term
Mucosa of the Large Intestine
Definition
NO plicae or villi (smoother walls)
Simple columnar epithelium (same epithelium as small intestine)
Goblet cells increase in density heading towards the rectum (as feces dries, need more mucous to propel)
Epithelium in anal canal = stratified squamous epithelium
Crypts of Lieberkuhn (intestinal crypts) are deeper in the large intestine
Term
Muscularis Externa of the Large Intestine
Definition
Cecum & Colon -> outer longitudinal muscle layer is in 3 distinct bands (teniae coli)
Rectum -> internal anal sphincter is a thickening of the inner circular layer of smooth muscle
Term
Which sections of the colon are intraperitoneal? Retroperitoneal?
Definition
Intraperitoneal = Transverse, Sigmoid
Retroperitoneal = Ascending, Descending
Term
Liver
Definition
Largest internal organ; 1.5 kg on average; located on R side of body
INTRAPERITONEAL (falciform & coronary ligaments; lesser omentum)
Filters venous blood via hepatic portal system; involved in the production of bile
Term
Surfaces of the Liver
Definition
Diaphragmatic = anterior, superior surface
Visceral = posterior, inferior surface
Term
Lobes of the Liver
Definition
Separated into R and L lobes by the Falciform Ligament
Caudate Lobe - anterior; superior to quadrate
Quadrate Lobe - posterior; in between gallbladder and L lobe
Caudate & Quadrate lobes are both on visceral surface
Term
Falciform Ligament
Definition
Mesentery (formerly ventral) that separates the R and L lobes of the liver
Round Ligament - thickening of the ligament, showing where the umbilical vein existed
Term
Coronary Ligament
Definition
Mesentery that connects the liver to the diaphragm anteriorly
Bare Area - area of liver in direct contact with diaphragm (no mesentery)
Term
Lesser Omentum
Definition
Connects the liver to the stomach
Term
Porta Hepatis
Definition
The hilum of the liver; contains the hepatic triad - hepatic artery proper, hepatic portal vein, bile duct
Term
What vessel brings the majority of the blood to the liver?
Definition
The hepatic portal vein
Term
What is the functional unit of the liver?
Definition
The liver lobule (lobules separated by CT); consists of hepatocytes running outwards in cords from the central vein; sinusoids run in between adjacent cords
Term
Where does the hepatic triad exist in relation to the liver lobule?
Definition
Exists on the periphery of the lobule; blood from the artery proper and portal vein enters sinusoids at peripheries and travels towards central vein
Term
Where do the nutrients filtered out of the sinusoids go?
Definition
They enter the perisinusoidal space; here, they are absorbed by the microvilli of the hepatocytes
Term
Path of blood entering and leaving the liver lobules
Definition
Blood enters lobule @ periphery from the hepatic triad (artery and portal vein); blood is absorbed into sinusoids and travels towards central vein; along the way, nutrients are transported into the perisinusoidal space where they can be absorbed by the microvilli of the hepatocytes
Remaining blood in sinusoids drains into the central vein where it is taken to the hepatic veins which connect to the IVC
Term
Hepatocytes involvement in bile production
Definition
Hepatocytes are also responsible for producing bile; bile is secreted into canaliculi which connect to the bile duct system
Term
Kupffer Cells
Definition
Phagocytes located in the walls of the sinusoids which remove foreign pathogens & debris from the blood
Term
What surface of the liver is the gall bladder associated with?
Definition
Connected to the anterior surface of the liver
Term
Path of bile leaving the liver lobules
Definition
Bile is secreted by hepatocytes into canaliculi which drain into the L and R hepatic ducts; these ducts merge to form the common hepatic duct
Common hepatic duct bile has two options:
- Continue to the common bile duct to empty into duodenum
- Continue to the cystic duct and drain into gallbladder for storage & concentration
Term
Gall Bladder
Definition
Functions to store excess bile and concentrate stored bile
Small pear shaped muscular sac
Cystic duct connects gallbladder to the common hepatic duct/common bile duct
Term
Cystic Duct
Definition
Serves as a conduit for bile from the common hepatic duct to the gallbladder
2-way duct - bile can travel to and from the gall bladder via the cystic duct
Term
Blood Supply to the Gallbladder
Definition
Supplied by the cystic artery
Term
Regions of the Gall Bladder
Definition
Fundus - region that pokes out from under the liver
Body - main portion
Neck - junction w/ cystic duct
Term
What is responsible for controlling secretion of bile from the gallbladder?
Definition
CCK secreted by enteroendocrine cells of the crypts of Lieberkuhn in the small intestine
Term
What does the secretion of bile aid in?
Definition
Secretion of bile aids in the digestion of fats
Term
Hepatopancreatic Sphincter (of Oddi)
Definition
Closes off common bile duct before duodenal ampulla; release of CCK relaxes sphincter so bile can flow in (along w/ pancreatic juice)
Term
Where does the common bile duct join with the pancreatic duct?
Definition
At the duodenal ampulla; then bile and pancreatic juice enter the small intestine at the duodenal papilla
Term
What gives bile its green-yellow colour?
Definition
Bilirubin - byproduct of Hb degradation
Term
What type of epithelium lines the gallbladder?
Definition
Simple columnar epithelium w/ microvilli (similar to epithelium of the small and large intestines)
Term
Histology of the Gall Bladder
Definition
NO muscularis mucosa; little submucosa
Muscularis externa consists of scattered muscle fibers
Outer adventitia (NO serosa)
Term
Gall Stones
Definition
Formed by the calcification and precipitation of bile
Typically get stuck in the neck of the gallbladder; more harmful if stuck in common bile duct
Term
Pancreas
Definition
RETROPERITONEAL; head located next to duodenum; tail located next to spleen
Term
Pancreatic Duct (of Wirsung)
Definition
Joins w/ the common bile duct @ duodenal ampulla
Travels through the entire pancreas
Term
Blood Supply / Drainage of the Pancreas
Definition
Head = supplied by the celiac and superior mesenteric arteries
Tail & Body = supplied by the splenic artery

Drainage to hepatic portal is by equivalent veins for each
Term
Exocrine Histology of the Pancreas
Definition
Functional unit = acinus
The acini empty secretions into small ducts which drain into pancreatic duct of Wirsung
Secretes - enzymes for digestion, bicarbonate ions; creates an alkaline pancreatic juice to buffer and neutralize acids from the stomach
Term
Pancreatic secretions are regulated by?
Definition
CCK and secretin secreted by enteroendocrine cells of the small intestine glands
Term
Where are the taste buds specific for "umami" found?
Definition
In the circumvallate papillae
Term
Which salivary glands are the largest by size?
Definition
The parotid glands
Term
Which salivary glands produce the most saliva, on a daily basis?
Definition
Submandibular glands
Term
The greater omentum is connected to which curvature of the stomach?
Definition
Connected to the greater curvature (lateral); greater omentum is the dorsal mesentery which secures the stomach to the posterior abdominal wall
Term
Which nerve plexuses mainly control the contraction of the muscles of the small intestine?
Definition
Myenteric (Auerbach's) plexus and submucosal (Meissner's) plexus
Term
What is the transition of epithelium in the rectum?
Definition
Proximal rectum = simple columnar
Distal rectum = stratified squamous
Term
What are the cartilages that make up the body of the larynx made of?
Definition
Cricoid & Thyroid = hyaline cartilage
Epiglottis = elastic cartilage
Term
What is the epithelium of terminal and respiratory bronchioles?
Definition
Simple cuboidal (non-ciliated)
Term
Which T cell is known for direct cell mediated immunity?
Definition
Cytotoxic T cells, as these cells directly attack foreign pathogens
Term
What is the structural framework of red pulp?
Definition
Reticular fibers
Term
What type of capillaries exist in the spleen?
Definition
Sinusoids.

Filtered blood collects into sinusoids, which drain into trabecular veins which empty at the hilus of the spleen
Term
Brunner's Glands
Definition
Exist in submucosa of duodenum and secrete an alkaline mucous to neutralize acidic contents of the stomach
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