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Veterinary Anat and Phys 2
Flash cards for vet anat 2 semester 2
49
Anatomy
Undergraduate 1
02/03/2008

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Term

 

 

 

 

 

Urinary system 

Definition
Most important single route waste product removal in body, especially soluble waste and excess water
 
 - respiratory system removes CO2 and water vapour 
 - sweat glands remove water, salts, some urea
 - digestive system removes bile salts, and pigments
 - urinary system removes urea, salts, water and other soluble products
 
2 kidneys
2 ureters
1 urinary bladder
1 urethra
 
Kidney = greek nephr/o, latin ren/o
 
-produce urine to eliminate metabolic wastes
-maintain homeostasis
 
 -blood filtration, reabsorption and secretion
 -fluid balance regulation
 -acid-base balance regulation
 -hormone production (erythropoeitin and prostaglandins 
Term

 

 

 

 

 

Kidneys 

Definition
renal pelvis: funnel-shaped collection chamber inside hilus, beginning or ureter, transitional epithelium lined; not in cattle
 
outer renal cortex, rough appearance
 
inner renal cortex, smooth appearance
 
Multipyramidal/multilobar (pig, cattle)
 
Unipyramidal/unilobar (dog, cat, horse)
 
Calyx: cup-like extension renal pelvis 
Term

 

 

 

 

Nephron 

Definition
-basic functional unit of the kidney
 
-microscopic filtering, reabsorbing and secreting systems
 
-renal corpuscle
 
-proximal convoluted tubule
 
-loop of henle
 
-distal convoluted tubule
 
 
Term

 

 

 

 

 

Parts of Nephron 

Definition
renal corpuscle in cortex, filters blood, fluid called glomerular filtrate
 - glomerulus: tuft of capillaries
 - bowman's capsule: double walled  (parietal and       visceral layers); space between, capsular space 
 
Proximal convuluted tubule (PCT) longest, twisting
 -continuation of capsular space of bowman's capsule; in cortex
 -cuboidal epithelial cells with brush border
 -becomes tubular filtrate (primitive urine)
 
Loop of Henle
 -U-turn into medulla, cuboidal cells, brush border
 -simple squamous epithelium, ascends into cortex
 
Distal convuluted tubule (DCT)
 -continuation distal loop of henle in cortex
 -empty into collecting ducts, carry tubular filtrate
   -ADH site of action
   -K+ regulation, control of acid-base balance
Term

 

 

 

 

 

Blood supply 

Definition
25% blood pumped by heart goes to kidneys
 
circulating blood passes through every 4-5 mins
 
abdominal aorta >renal artery (enters hilus)>arteries> arterioles>afferent glomerular arterioles> glomerular capillaries (filter plasma out, into capsular space of bowman's capsule, now glomerular filtrate)>efferent glomerular/peritubular capillaries (O2 transfer)> venules>veins>renal vein> abdominal vena cava 
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Waste Elimination 

Definition
Filtration
 - in renal corpuscle, high blood pressure forces plasma from glomerular capillaries (many pores) into capsular space
 - glomerular filtrate contains no protein or cells
 - Glomerular Filtration Rate:measure how fast plasma filtered as passes through glomerulus; depends on rate of blood flow to kidney
 
Reasorption
 
Secretion
 
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Reabsorption 

Definition
glomerular filtrate contains wastes and Na, Ca, K, Mg, glucose, amino acids, Cl, HCO3, and water all required to maintain homeostasis
 
becomes tubular filtrate in PCT, Na pumped out (reabsorbed), glucose and amino acids follow passively, into interstitial fluid, then into peritubular capillaries
 
Aldosterone influences reabsorption of Na from loop of henle and distal convulted tubule, exchanged for H, NH3, K
 
K, Ca, Mg (influenced by PTH - parathyroid hormone), reabsorbed in Proximal convoluted tubule, loop of henle, Distal convoluted tubule and or collecting ducts
 
Cl reabsorbed by diffusion, water follows by osmosis, urea also
 
65% reabsorbed in PCT (80% water, Na, Cl, HCO3, 100% glucose and amino acids) 
Term

 

 

 

 

 

 

Secretion 

Definition
Transfer from peritubular capillaries to interstitial fluid, tubular epithelial cells, to tubular filtrate (opposite of reabsorption), mostly in distal convoluted tubule
 
waste products and foreign substances not being filtered sufficiently in glomerulus: H, K, NH3, drugs (penicillin, sulfonamides)
 
Term

 

 

 

 

 

Urine Volume 

Definition
determined by amount of water in tubular filtrate when reaches renal pelvis
 - ADH increases water reabsorption (DCT, collecting ducts)
 - Aldosterone increases Na reabsorption, water follows by osmosis (DCT, collecting ducts), if ADH present
 
pressure in bowman's capsule > renal pelvis, forces fluid to move along through the tubules of the nephron 
Term

 

 

 

 

 

Ureters 

Definition
continuation of renal pelvis, leave kidneys at hilus
 
layers: outer fibrous, middle smooth muscle, inner transitional epithelium
 
urine moved to bladder by peristalsis, walls can stretch
 
enter bladder at oblique angle; when bladder full, prevents retrograde flow of urine towards the kidneys, but urine can still enter bladder due to peristalsis
 
Term

 

 

 

 

 

Urinary bladder 

Definition
collects, stores, and releases urine
 
muscular sac and neck, lined with transitional epithelium, muscle:
 - involuntary smooth muscle bundles - run length wise, obliquely and circular directions
 - voluntary skeletal muscles - sphincter at neck
 
urination (micturation or uresis) controlled by 
1)urine accumulation
2)smooth muscle contraction
3)sphincter muscle control 
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Control of urination 

Definition
urine accumulation until pressure reaches trigger point, stretch receptors in bladder wall activated
 
spinal reflex returns motor impulse to smooth muscles to contract, urge to urinate
 
voluntary control of sphincter muscles (house training); limit to bladder capacity, walls thinner with stretching, can rupture 
Term

 

 

 

 

 

Urethra

 

Definition
Continuation of bladder neck, transitional epithelium lined, carried urine to outside of body
 
shorter and wider in females, open in ventral vagina
 
long and narrow in male, down center of penis; vas deferens and accessory sex glands enter: during ejaculation, sperm and seminal fluid discharged and urinary sphincter closes 
Term

 

 

 

 

 

Renal Dysfunction and Uremia 

Definition
urinary system unable to remove wastes from blood adequately: uremia (urine in blood) results, increased BUN
 
Prerenal uremia: decrease in blood flow to kidneys so waste products not removed (dehydration, congestive heart failure, shock) although kidneys functioning
 
Renal uremia: damage to nephrons (2/3 non-functional before clinical signs appear) by toxins, inflammation, infections;adequate blood flow but decrease functional neurons to filter wastes
 
Postrenal uremia: obstruction (tumors, blood clots, uroliths) preventing urine expulsion and decreas flow; eventually, urine backs up into renal pelvis, increase pressure that damages nephrons and leads to renal dysfunction
Term

 

 

 

 

 

Endocrine system 

Definition
works together with nervous system to maintain homeostasis
 
primary function: produces hormones
 
hormones act on specific target cells to produce specific effects
 
Term

 

 

 

 

 

Hormones 

Definition
chemical messengers produced by endocrine glands and secreted directly into blood vessels
 
produce effects when they find their specific receptors in or on cells
 
a cell that has receptors for a particular hormone is referred to as a target of that hormone
 
Term

 

 

 

 

Control of hormone secretion 

Definition
negative feedback system:
 
when the level of a specific hormone drops below needed levels, the appropriate endocrine gland is stimulated to produce more hormone
 
once the proper hormone level is present in the bloodstream, stimulation of that endocrine gland is reduced and production of that hormone is reduced 
 
direct stimulation from the nervous system
 
Secretion of some hormones is stimulated by the sympathetic nerve impulses when and animal feels threatened (fight or flight response)
 
Term

 

 

 

 

 

Major Endocrine Glands 

Definition
Anterior pituitary
Posterior pituitary
Thyroid
Parathyroid
Adrenal cortex
Adrenal medulla
Pancreas (islets)
Testis
Ovary 
Term

 

 

 

 

 

Hypothalamus 

Definition
Part of diencephalon section of the brain
 
controls activities of the pituitary gland
 
portal system of blood vessls links hypothalamus with anterior portion of pituitary gland
 
modified neurons in the hypothalamus secrete releasing and inhibiting factors into portal blood vessels
 - specific for a particular antieror putuitary hormone
 
modified neurons in the hypothalamus also secrete antidiuretic hormone and oxytocin
 
transported to posterior pituitary for storage
 
released into the blood stream by nerve impulses from the hypothalamus 
Term

 

 

 

 

 

Pituitary Gland (Hypophysis) 

Definition
Two separate gland with different structures, functions, and embryological origins
 
Anterior pituitary - adenohypophysis; rostral portion
 - stimulated by hypothalamus and direct feedback from target organs and tissues to produce its hormones
 
Posterior pituitary - neurohypophysis; caudal portion
 - stores and releases hormones produced in hypothalamus 
Term

 

 

 

 

The Anterior Pituitary

hormones 

Definition
F - (FSH)- Follicle Stimulating Hormone
L - (LH)- Luteinizing hormone
A - (ACTH)- Adrenocorticotropic Hormone
T - (TSH)- Thyroid Stimulating Hormone 
G - (GH) - Growth Hormone
M - (MSH) - Melanocyte Stimulating Hormone
P - Prolactin 
 
Term

 

 

 

 

 

Growth Hormone 

Definition
also known as somatotropin and somatotropic hormone
 
promotes body growth in young animals
 
helps regulate the metabolism of proteins, carbs, and lipids in al the body's cells 
Term

 

 

 

 

Prolactin 

Definition
Helps trigger and maintain lactation
 - secretion of milk by the mammary glands
 
Prolactin production and release continues as long as the test or nipple continues to be stimulated by nursing or milking
 
When prolactin stimulation stops, milk production stops, and the mammary gland shrinks back to ist nonlactating size 
Term

 

 

 

 

 

Thyroid Stimulating Hormone 

Definition
also known as thyrotropic hormone
 
stimulates growth and development of thyroid gland and causes it to produce its hormones
 
secretion is regulated by feedback from the thyroid gland
 - has direct effects on anterior pituitary gland through changes in TSH - releasing factor produced by the hypothalamus 
Term

 

 

 

 

 

Adrenocorticotropic Hormone (ACTH) 

Definition
stimulates growth and development of the adrenal cortex and release of some of its hormones
 
regulated by feedback from the hormones of the adrenal
 
ACTH can also be released quickly as a result of stimulation of the hypothalamus by other parts of the brain
 - hypothalamus sends a burst of ACTH - releasing factor to the anterior pituitary through the portal system causing ACTH to be released quickly 
Term

 

 

 

 

 

Follicle Stimulating Hormone  (FSH)

Definition
in female, stimulates growth and development of ovarian follicles - oogensis
 - also stimulates cells lining the follicles to produce and secrete estrogens
 
in the male, stimulates spermatogenesis 
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Luteinizing Hormone (LH) 

Definition
after ovulation,LH stimulates cells in the empty follicle to multiply and develop into the corpus luteum
 - corpus luteum produces progestin hormones necessary for the maintenace of the pregnancy
 
in the male, LH stimulates interstitial cells to develop and produce testosterone 
Term

 

 

 

 

 

Melanocyte Stimulating Hormone (MSH) 

Definition
associated with control of colour changes in the pigment cells (melanocytes) of reptiles, fish, and amphibians
 
administration of artificially large amounts of MSH to higher mammals can cause darkening of the skin from melanocyte stimulation 
Term

 

 

 

 

 

The Posterior Pituitary

 

Definition
stores two hormones produced in the hypothalamus
 
antidiuretic hormone and oxcytocin
 
transported from hypothalamus to posterior pituitary and stored in nerve endings
 
periodically released into the bloodstream in response to nerve impulses from hypothalamus 
Term

 

 

 

 

 

Antidiuretic Hormone (ADH)

 

 

Definition
Helps prevent diuresis
 
receptors in hypothalamus detect changes in osmotic pressure of blood that result from dehydration/hemoconcentration
 
generates nerve impulses - causes release of ADH
 - ADH travels to the kidney - causes kidneys to reabsorb more water from the urine and return it to the bloodstream
 
ADH deficiency causes diabetes insipidus 
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Oxytocin 

Definition
effects on uterus - causes contraction of the myometrium at the time of breeding and at parturition
 - increases uterine contractions that aid transport of spermatozoa to the oviducts
 - stimulates uterine contractions that aid in the delivery of the fetus and the placenta
 
Effect on active mammary glands - causes movement of milk down to the lower parts of the gland (milk letdown)
 - stimulation of the test or nipple by nursing or milking causes oxytocin to be released into the bloodstream
 - causes contraction of the myoepithelial cells around the mammary gland alveoli and small ducts
 - forces milk into the lower parts of the gland 
Term

 

 

 

 

Thyroid Gland, hormones and effects of the hormones

Definition
The Thyroid Gland
consists of 2 lobes on either side of the larynx
 - lobes may be connected by isthmus
 
thyroid hormone is produced in follicles
 - simple cuboidal glandular cells surrounding globule of thyroid hormone precursor
 
Thyroid Hormones 
T3 (triiodothyronine) and T4 (tetraiodothyronine, or thryoxine)
 
produced in greater abundance then T3
 but is mostly converted to T3 before producing effects on target cells
 
Effects of Thyroid hormones 
influences development and maturation of CNS, growth and development of muscles and bones
 
caloringenic effect - regulates the metabolic rate of all the body's cells
 
allows animal to generate heat and maintain constant internal body temp
 
production increases with exposure to cold and then increasses metabolic rate to generate more heat
 
affects metabolism of proteins, carbs, and lipids like GH does 
 
 
 
 
 
 
 
Term

 

 

 

 

 

 

Calcitonin 

Definition
produced by C cells located between thyroid follicles
 
helps maintain blood calcium levels
 
prevents hypercalcemia by encouraging  excess calcium to be deposited in the bones
 
calcium is involved in muscle contraction, blood clotting, millk secretion and formation and mainenance of the skeleton 
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Parathyroid Hormone (PTH) 

Definition
also called parathormone
 
produced by the parathyroid glands
 - small, pale nodules in, on or near the thyroid glands
 
helps maintain blood calcium levels
 
prevents hypocalcemia
 - causes kidneys to retain calcium and intestine to absorb calcium from food; withdraws calcium from bones 
Term

 

 

 

 

 

The Adrenal Glands 

Definition
located near the cranial ends of the kidneys
 
consist of two glands
 
1) adrenal cortex
2) adrenal medulla 
Term

 

 

 

 

The Adrenal Cortex 

Definition
Produces numerous steroid hormones classified into 3 main groups
 
1) Glucocorticoids: cortisone, cortisol, and corticosterone
 - hyperglycemic effect
 - Also helps maintain BP and help the body resist the effects of stress 
 
2) Mineralocorticoids: eg) aldosterone
 - regulates the level of important electrolytes (mineral salts) in the body
 
3) Sex Hormones: androgens and estrogens
Term

 

 

 

 

 

Adrenal Medulla 

Definition
produces epinephrine and norepinephrine
 
sectretion is controlled by the sympathetic portion of the autonomic nervous system (fight or flight response)
 
increases heart rate and output, increases blood pressure, dilates air passageways in the lungs, and decreases GI function 
Term

 

 

 

 

 

Pancreas and Pancreatic hormones

Definition
located near the duodenum
 
has both exocrine and endocrine functions
 
endocrine component- small percentage of the total volume of the organ
 
pancreatic islets (islets langerhans): groups of cells scattered throughout the pancreas
 - alpha cells - produce glucagon
 - beta cells - produce insulin
 - delta cells - produce somatosin 
 
Pancreatic Hormones 
Insulin: lowers blood glucose levels by causing glucose, amino acids and fatty acids to be absorbed into body cells
 
Glucagon: raises blood glucose levesl by stimulating liver cells to convert glycogen to glucose by stimulating gluconeogenesis
 
Somatostatin: inhibits secretion or insulin, glucagon, and GH; diminishes GI activity 
 
Term

 

 

 

 

 

Testes 

Definition
Interstitial cells: clumps or endocrine cells
 
Produce androgens when stimulated by LH
 - interstitial cell stimulating hormone (ICSH) in the male
 
Testosterone: primary adrogen
 - provides for development of male secondary sex characteristics and accessory sex glands
 - activates spermatogenesis 
Term

 

 

 

 

Ovaries 

Definition
Produce ova and hormones in cycles
 
controlled by follicle stimulating hormone (FSH) and luteinizing hormone (LH)
 
Hormone groups produced in the ovaries:
1) estrogens
2) progestins 
Term

 

 

 

 

Estrogens 

Definition
FSH stimulates ovarian follicles to develop
 - cells of follicles produce and release estrogens
 - amount or estrogen produced increases as follicle grows
 
Increasing estrogen levels accelerate physical and behavioural changes
 
feedback to anterior pituitary
 - cause anterior pituitary gland to reduce the production of FSH and increase the production of LH
 
When follicle is fully mature, LH level peaks
 - in most animal species, ovulation occurs when LH level peaks 
Term

 

 

 

 

 

Progestins 

Definition
group of hormones produced by corpus luteum
 
high LH level stimulates cells of empty follicle to multiply and develop into corpus luteum
 
progesterone - principle progestin 
 - helps prepare uterus tor receive fertilized ovum; needed to maintain pregnancy
 
in pregnant female, hormone signal is sent from uterus, and corpus luteum is maintained
 
if no pregnancy occurs, lack of hormone signal causes corpus luteum to shrink and disappear 
Term

 

 

 

 

 

Kidneys 

Definition
produce erythropoeitin - stimulates red bone marrow to increase production of RBCs
 
production of erythropoeitin stimulated by hypoxia
 
as RBC production increases, more oxygen feeds back to kidneys and slows the production of erythropoeitin 
Term

 

 

 

 

 

Stomach 

Definition
gastrin: produced by cells in teh wall of the stomach
 
secretion stimulated by presence of food in the stomach
 
stimulates gastric glands to secrete hydrochloric acid and digestive enzymes
 
encourages muscular contractions of the stomach wall 
Term

 

 

 

 

 

Small Intestine 

Definition
secretin and cholecystokinin produced by cells in the lining of the small intestine
 
secretion occurs in response to presence of chyme in duodenum
 
secretin stimulates pancreas to secrete fluid to neutralize acidic chyme after it passes out of the stomach
 
Cholecystokinin stimulates pancreas to releas digestive enzymes into the duodenum 
Term

 

 

 

 

Placenta 

Definition
Surrounds a developing fetus during pregnancy
 
acts as an interface with the maternal circulation
 
produces hormones to help support and maintain pregnancy
 - estrogen and progesterone
 - chorionic gonadotropin (some species) 
Term

 

 

 

 

 

Thymus 

Definition
extends cranially from the level of the heart up into neck region along both sides of the trachea
 
large in young animals, atrophies later in life
 
function involves hormones or homonelike chemical substances (ed. thymosin and thymopoeitin)
 
seems to cause certain cells to be transformed into T-lymphocytes 
Term

 

 

 

 

 

Pineal Body 

Definition
located at caudal end of cleft that separates the 2 cerebral hemispheres
 
influences cyclic activities in the body
 
melatonin-hormonelike substance called that seems to affect moods and wake-sleep cycles
 - may also paly a role in the timing of seasonal estrous cycles in some species 
Term

 

 

 

 

 

Prostaglandins 

Definition
hormonelike substances derived from unsaturated fatty acids
 
produced in a variety of body tissues (skin, intestine, brain, kidney, lungs, reproductive organs, and eyes)
 
nine main groups- designated groups A through I
 - subscript numbers and Greek letters designate subgroups
 
influence blood pressure, blood clotting, inflammation, GI, respiratory, reproductive, and kidney function 
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