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A&P Test 3
A&P 1 test 3
122
Anatomy
Undergraduate 2
11/03/2011

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Term

Functions of Skeletal System

Definition
Support, protection movement mineral storage blood cell production and fat storage
Term
Bone Tissue
Definition

A kind of connective tissue.
Crystals of inorganic calcium salts make it more     rigid than other connective tissues.
Network of collagen fibers provides flexibility and strength.

Term
Skeletal system
Definition

Frame work of bones and cartilage composed of various tissues

 

Bone, Cartilage, Epithelium, Fat, and Neurons

Term
Compact or dense bone tissue
Definition

Contains few spaces.
Forms a layer over spongy bone.
Provides protection support and strength.
Has a concentric ring structure.

Term
Spongy or cancellous bone tissue
Definition

Contains many large spaces
Makes up most of the bone tissue of the skull bone, vertebrae and the Epiphyses or “tip” of long bone
Lattice works of thin bone plates are called trabeculae
In some bones the spaces are filled with red marrow which produces blood cells
provides the greatest strength with the least weight

Term
Parts of a typical long bone
Definition
Diaphysis, Epiphysis, Metaphysis
Term
Diaphysis
Definition
Shaft of the bone
Term
Epiphysis
Definition
Tips of the bone
Term
Metaphysis
Definition

Region of the bone that connects the epiphysis to the diaphysis

 

Also contains the episyseal plate (where bone growth occures

Term
Medullary or marrow cavity
Definition
Space within the diaphysis
Contains fatty yellow marrow in adults
Term
Endosteum
Definition
Layer of osteoblast lining the marrow cavity and scattered osteoclast
Term
Osteoblast
Definition
bone cell that makes the bone
Term
Osteoclast
Definition
Bone cell that degrades the bone
Term
Articular cartilage
Definition
Thin layer of cartilage covering the epiphysis at a joint with another bone
Term
Periosteum
Definition
Fibrous covering around the bone where it is not covered by articular cartilage
Which Consist of Connective tissue containing blood vessels, Lymphatic vessels, Nerves, and Cells that become osteoblast
Term

Osteons or haversian system (functional units of the bone)

Definition
Structural unit of bone
Elongated cylinder parallel to bones long axis
Function as weight bearing pillars
Osteons is a hollow tube of bone Like rings on a tree, the rings are called lamella.
Collagen fibers in adjacent lamella run in opposite directions

Term
Central or haversian canals
Definition
Canal that runs through the center of the osteons
Contains small blood vessels and Nerve fibers
Term
Perforation of Volmann’s canals
Definition
Lie at right angles to the central canal
Connect nerves and blood vessels in central canals with rest of the body (perpendicular to the long axis of the bone)
Term
Osteocytes
Definition
Mature bone cells that is found in lacunae at the junctions of the lamellae
Canaliculi connect lacunae
Term
Circumferential Lamellae
Definition
Located on the outside or surface of the shaft
Surround the osteons inside of the bone
Like bark on a tree
Term
Ossification
Definition

Bone formation

Embryo begins with a ‘skeleton’ of cartilage and fibrous membranes shaped like bones
begins about 6-7 weeks right after conception and continues throughout adulthood
Embryonic connective tissue cells multiply and enlarge and form cartilage and bone
Once a framework is made, calcification occurs, Calcium is deposited making the bone hard

Term
Order of Ossification in Long Bone
Definition
Shaft ossifies first
Epiphyses ossify secondarily
Epiphyseal plate between the shaft and ends remains cartilage
`Permits growth of the bone shaft
When lengthening stops the epiphyseal plate becomes the epiphyseal line
Term
During Growth
Definition
Bones also increase in diameter during this
Term
Bones remodele
Definition
Constantly, which allows bones and blood to exchange calcium
Term
Osteoblast
Definition
Makes the bone
Term
Osteoclast
Definition
Destroys the bone
Term
Diet Must be High in
Definition
Calcium, Phosphorus, Vitamin D
Term
Bone regulation hormones
Definition
Growth hormone, Calcitonin, Parathyroid hormone, and Serotonin
Term
Growth Hormone
Definition
Pituitary gland in the brain, Regulates general body growth
Term
Calcitonin
Definition
Thyroid gland in the throat, it promotes calcium deposistion into the bone
Term
Parathyroid Hormone
Definition
In the throat, Promotes removal of calcium from the bones, Osteoclast
Term
Serotonin
Definition

Made in the intestine, its a neurotransmitter, it also inhibits osteoblast production

Shifts balance to the osteoclast, helping with bone degradation

Term
When blood concentration of Ca2+ is too high
Definition

 the Rising blood levels of stimulate calcitonin release
Calcitonin stimulates the osteoblast to deposit Ca2+ into the bones
Ca2+ Concentration of blood returns to the homeostatic level

 

Term
When blood concentration of Ca2+ is too low
Definition

Falling Ca2+ levels stimulate parathyroid hormone release
Hormone stimulates osteoclast to degrade the bond
Ca2+ is released into the blood
Ca2+ levels in blood increase to the homeostatic level

Term
Remodeling and mechanical factors
Definition
Functions to strengthen parts of the skeleton that are under stress
Not sure how it occures..may involve locally produced growth factors that stimulate the osteoblasts
Aging shifts the balance between organic matter and calcium in bones
More inorganic salts and less organic matter
Causes less flexible and more brittle bones
Term
Sex, Female
Definition
Wide and oval-shaped pelvic opening, small eyebrow ridge
Term
Sex, Male
Definition
Narrow pelvic opening and its heart-shaped
Thicker skulls
Dominate eyebrow ridge
Term
What bones can tell you, Age
Definition
Different bones have specific times that they stop growing
Teeth erupt at specific ages
Tooth wear
Term
Other Info that bones can tell you
Definition
Based on minerals incorporated into bones:
Diet
Location person grew up based on the proportions of isotopes in the bones
Term
What Bones Can tell you
Definition
Muscle size and activities of a person
Term
Muscles make up how much body weight
Definition
30-50% and there are over 600 skeletal muscles in the body
Term
Muscle Characteristics
Definition
Excitability - response to a stimulus
Contractility - ability to contract
Extensibility - ability to extend
Elasticity - ability to stretch
Conductivity - a muscle can conduct a nerve impulse from one muscle to another
Term
Muscular Functions
Definition
Motion, Maintenance of posture, and hear production
Term
Skeletal Muscle
Definition
Attached to bones, (for the most part) and moves parts of the skeleton
Makes up what we usually think of as muscle
Term
Skeletal Muscle Cells
Definition
Very long (ten times the normal size)
Cylindrical fibers - cylinder like
Multi-nucleated (large cells)
Have prominent striations
Term
Skeletal Muscle Contractions
Definition
Slow to fast
Forceful
Not rhythmic (unless your mind tells them too)
Voluntary
Term
Skeletal Externally Visible Movments
Definition
Locomotion - walking running
Grasping with fingers
 Respiration and Swallowing
Food manipulation and speech
Expression of mood and emotion
Term
Fascias
Definition

Superficial fascia

Deep fascia

Term
Superficial Fascia
Definition
Lies just under the skin
Composed of adipose and loose connective tissue
Stores fat and water
Insulates the body (the fat)
Provides mechanical protection from blows
 Pathway for blood vessels and nerves
Term
Deep Facia
Definition
Lines the body wall and surrounds groups of muscles
Allows free movement of muscles
Pathway for nerves and blood vessels
Sometimes it is the origin for muscles

Term
Tendons
Definition
Cords of fibrous connective tissue
Attach a muscle to a bone, they are not very elastic
Tendons pull bones in the direction of the contraction
Important in the hands and feet
`Permit a highly mobile appendage without the bulk of muscles
Ligaments are like tendons except they connect bone to bone
` Joint

Term
Aponeurosis
Definition
A broad, flat sheet of dense connective tissue
Join two or more muscles together, or to a bone

Term
Myofibers (Largest)
Definition

Muscle cells, Long cylindrical cells visible under a microscope, Each fiber is surrounded by a sheath of connective tissue Largest cells (10x average size cells) Contain multiple nuclei
The cytoplasm is the sarcoplasm (sarco = muscle)
Myoglobin - a molecule that stores oxygen in muscles (also makes the muscle red or pink)

 

Term
Connective Tissue
Definition
Muscles are arranged in a series of bundles
`Small to large
Endomysium, Perimysium, Epimysium,
Term
Endomysium
Definition

Surrounds a single myofiber
Contains:
Blood capillaries

Nerve fibers       
                     They^ nourish and stimulate the cell

Term
Perimysium
Definition
Surrounds the fascicles (bundles of muscle cells)
Carries larger blood vessels and nerves
Term
Epimysium
Definition
Surrounds several fascicles that together compose a muscle, Separates a muscle from the surrounding muscles or tissues, Carries blood vessels and nerves
Term
Myofibrils (Second Largest)
Definition
Rod like super-organelles (only found in muscle cells) Oriented lengthwise and parallel the length of the cell Contractile elements of muscle cells
Composed of smaller contractile units called sarcomeres (entire row on the ceiling is one myofibrils, each individual tile is the sarcomeres)

Term
Striations
Definition
Series of light and dark bands along the length of the myofibril
A bands - dark bands
I bands - light bands
H zone - a light stripe in the middle of the A band
Z disk - dark midline of the I band

Term
Sarcomere
Definition
Functional unit of the muscle fiber
Part of a myofibril that is between two Z disks

Term
Myofilaments
Definition
Are structures within the sarcomere
` There are two kinds (Thick and Thin)
Term
Thick Filament
Definition
Go across the A band, Made of myosin
 Myosin -- A protein with a rod like tail end and two globular heads on the other end
Globular heads are called cross bridges
`Link the thick and thin filaments together during contractions

Term
Thin Filaments
Definition
Cross the I band and extend into the A band
Made of
Actin,Troponin,Tropomyosin
Term
Sarcoplasmic Reticulum (SR)
Definition
Smooth ER
Regulates intracellular calcium levels (Ca2+)
Stores Ca2+ when the muscles is not contracted
Releases Ca2+ when the muscle is contracted

Term
T-tubules
Definition
Transverse tubules, Folds of the cell membrane that penetrate the cell, Oriented at right angles to the myofilaments, Functions to synchronize muscle contractions

Term
Skeletal muscle contractions
Definition
During contraction individual sacromeres shorten causing the cell to shorten Thick and thin filaments do not change length                 They ^ slide past each other In a relaxed myofiber the thick and thin filaments slightly over lap, During contractions the thin filaments slide in a contracted myofiber they overlap to a much greater degree
Term
Sliding of the think filaments
Definition
Sliding of the think filaments
Nerve impulse stimulates the release of Ca2+from the SR
Increases the intracellular Ca2+ concentration
Ca2+ binds to troponin
Troponin changes shape, Causing tropomyosin to slide
Which exposes the myosin binding site on actin
Myosin cross bridge attach to the myosin binding site on actin
Cross bridges attach and detach many times
---Acts like a ratchet pulling the thin filament inwards
Action continues as long as the Ca2+ concentration is high
Term
Steps in Skeletal Muscle Contraction
Definition
Cross bridge attachment, Power Stroke, Cross bridge detachment, Cocking of the myosin head,
Term
Cross Bridge Attachment
Definition
Activated myosin heads are attached to the myosin binding sites
Cross bridge binding occurs
Term
Power stroke
Definition
Occurs when the myosin head binds to the actin:
        a: Myosin pivots ,b: Changes from a high energy shape to a low energy shape
Pivoting of the myosin head pushes the thin filaments towards the sarcomeres center
Simultaneously ADP & P are released from the myosin head, ADP & P are left over from the previous contraction

Term
Cross bridge detachment
Definition
A new ATP molecule binds to the head
Causing it to change shape
Head is released from the myosin binding site on actin

Term
Cocking of the myosin head
Definition
Myosin head is cocked by converting ATP to ADP & P
Provides the potential energy for the contraction
ADP & P remain attached to the myosin head in this step  
Term
Back Where We Started (Cross Bridge Attachment)
Definition
Myosin head is ready for a cycle, Continuing process moves the thin filament towards the sarocomeres center, The thin filament does not slide bak when a single myosin head detaches, Some myosin heads remains attached
Muscles relaxes when calcium is pumped back into the SR
Troponin resumes its normal shape, Causes tropomyosin to slide and cover the myosin cites on actin
Term
Regulating of binding contracting
Definition
An action potential is required for a skeletal muscles contractions and action potential (AP) = nerve impulse = electrical current
AP causes a temporary rise in the intracellular Ca2+ concentration
The rising Ca2+ concentration stimulates the contraction
Term
Neuron muscular junction and the nerve impulse
Definition
Skeletal muscles are stimulated by motor neurons
Motor neurons are in the brain and are connected to muscles by axons
An axon is the arm of the neuron that carries a nerve impulse away from a nerve cell body, Axons are bundled into nerves, Axons subdivide when they enter a muscle and innervate different parts of the muscle, The axon terminal forms a neuromuscular junction with a single muscle fiber, Axon terminal does not touch the muscle fiber Axon terminal contains synaptic vesicles filled with acetylcholine, Acetylcholine is a neurotransmitter, Carries the AP across the synapsis,

Term
Synapsis
Definition
Area of close contact between nerve and muscle
Term
Synaptic cleft
Definition
Space between the axon and the muscle fiber
Term
When an AP reaches the axon terminal
Definition
Ca2+ Enters the axon
Ca2+ stimulates the exocytosis of acetylcholine
Acetylcholine diffuses across the synaptic cleft
Binds with receptors on the sarcolemma (muscle cell membrane)

Term
Muscle cell AP and contraction
Definition
Acetylcholine binds wit the muscle cell membrane
AP is stimulated on the membrane AP travels down the t-tubules, AP stimulates the release, of Ca2+ from the SR
Ca2+ causes the active sites on actin to become uncovered Ca2+ fall within 30 ms, An active Ca2+ pump moves Ca2+ back into the SR, When the Ca2+ fall sufficiently

Term
Ca2+ causes the active sites on actin to become uncovered
Definition
Ca2+ causes troponin to change shape
Causes tropomyosin to slide exposing the myocin binding site
Cross bridge attachment occurs
Term
When the Ca2+ fall sufficiently
Definition
Troponin assumes its normal shape
The actin myosin binding sites are covered and made unavailable
Term
Motor unit

Definition
Composed of the motor neuron and the muscle fibers that it innervates, Each muscle has at least one motor nerve with up to 100’s of axons, Each axon branches into many axon terminals, Each terminal forms a neuromuscular junction with a single muscle fiber, Stimulating a motor neuron causes all of the innervated muscle fibers to contract
Muscles with very fine movements have very small motor units
Term
Muscle twitch
Definition
A single brief stimulus which causes a muscle to quickly contract than relax
Muscle twitches are rarely observed
`Eye muscle twitch

Term
Graded muscle show a graded response
Definition
Most muscles show a graded response
Contractions that are long, smooth and very in strength Produced in two ways
Changing the speed of stimulation
Changing the number of motor units activated
Term
Wave summation and tetanus
Definition
If a muscle is stimulated by two identical stimuli
The second stimulus will cause a stronger contraction, Because the muscle is not completely relaxed after the first contraction, Ca2+ must still be inside the cells cytoplasm

Term
If the Muscle
Definition
Is stimulated increasingly faster
Relaxation time between contractions becomes less
Ca2+ concentration inside the cytoplasm will continue to increase
Term
Tetanus
Definition

is the continual smooth contraction of a muscle

 

Contraction continues until the muscle is fatigued and looses its ability to contract
Due to the loss of the muscles ability to generate ATP


Term
Multiple motor units summation 
Definition
Precisely controls the force of a muscle contraction
Enables the fine control of the strength of the contraction, `Accomplished by activating different numbers of fibers, Only a few motor units are stimulated for weak but precise movements

Term
Muscle tone
Definition
Skeletal muscles are in a constant state of slight contraction
Functions:
Keep muscles healthy but not produce movement
Stabilizes joints and maintains posture
Term
Kinds of contractions
Definition
Muscle tension
Isotonic contraction (moving something)
Isometric contractions
Term
Muscle tension
Definition
Force generated by o contracting muscle on some object, Load - resistance to movement in opposition to force, Muscle tension > muscle load
The object is moved

Term
Isotonic contraction (moving something)
Definition
--Muscle changes in length
For example it decreases the angle at the joint
Thereby moves the load
Tension remains constant during contraction

Term
Isometric contractions
Definition
Tension continues to increase during contractions
Muscle does not get any longer of shorter
Functions to hold something in place

Term
Muscle cramps = Charley horse
Definition
Sudden involuntary contractions or spasms of muscles
Often occur after workouts or at night
Last a few seconds to several minutes
Term
Physiological mechanism of Muscle Cramps
Definition
Caused by explosive hyperactivity of motor nerves
Several mechanisms, Spinal disinhibition
Abnormal excitability of the axon terminals
Spreading of muscle contraction by direct transmission or axon reflexes
Term
Muscle Cramp Causes
Definition
Its unknown, Straining or over using of a muscle
Dehydration, Imbalances in levels of sodium potassium chloride calcium and phosphate
 Insufficient blood getting to muscle
Insufficient stretching before exercise
Exercising in the heat, Muscle fatigue spinal cord injury or a pinched nerve in the neck or back

Term
Muscle metabolism
Definition
ATP provides the energy for the contractions
Their is only 4-6 seconds worth of ATP help in reserve in muscles
More APT is generated in 3 ways
Term
Activation of ADP by creatine phosphate
Definition
A high energy molecule store in muscles
Small amino acid like molecule
Used to phosphorylate ADP
Stored ATP & creation phosphate supply enough energy for about 15-20 seconds of contractions
Term
Aerobic respiration
Definition
ATP is obtained from the breakdown of glucose or other energy yielding molecules
Glucose will come from glycogen
Process yield - 36 ATP per glucose molecule
O2 and other molecules must be present

Term
Anaerobic respiration (or metabolism)
Definition
First stage of glucose respiration, Process is know as glycolysis
Splits one molecule of glucose into 2 molecules of pyruvic acid, Net yield of 2 ATP, Process does not use O2, Pyruvic acid is broken down into Co2 and water during aerobic respiration, After prolonged exercise O2 demand does not equal oxygen supply, If O2 is lacking pyruvic acid its converted into lactic acid, Muscles become fatigued
They are not getting enough ATP to continue to contract


Term
Fatigue occurs when muscles are physiologically unable to contract

Definition
Occurs when there is a relative deficit of ATP
A total absence of ATP results in a constant state of contraction, because ATP required to release the myosin heads from actin
Rigor morit
Term

Causes of muscle fatigue
Definition
Exact cause is uncertain
Inadequate release of Ca2+ from SR
Insufficient O2
Glycogen and glucose depletion
 Lactic acid and ADP build up
Term
Sore Mucles
Definition
Lactic acid and ion imbalances are partially responsible
Term
For muscle to return to its resting state
Definition
Normal O2 concentration of the muscle must be restored
All of the lactic acid must be converted back into
Glycogen, and Glucose
Term

Force of a contraction is affected by
Definition
The number of muscle fibers stimulated
The relative size of muscles diameter and length
Series elastic elements
Term
For a muscle to work requires
Definition
Muscle must be attracted to a moveable object
Connective tissues and tendons must be pulled tight
The more rapidly a muscle is stimulated the greater force it generates`` because it takes less time to transfer the force to the series - elastic elements, When the contractions is slow --Forces dissipated before it can be transferred to the series- elastic elements
Term
Degree of muscle stretch 
Definition
Ideal resting length is when the myosin and actin fibers barely overlap, Can be greatly compressed
Significant overlap produces the distance the muscle can contract

Term
Load
Definition
Muscles are attached on both ends so they always have a load, Lighter the load the faster the contraction, Larger the load the slower and shorter the contraction

Term
Red slow twitch fibers
Definition
Energy primarily from aerobic respiration
Lots of mitochondria, Rich capillary supply
Fatigue resistant and high endurance
Fibers are thin so they don't generate much power
Lots of myoglobin

Term
White fast twitch fibers
Definition
White or pale have little myoglobin, More powerful that red fibers, ‘-Twice the diameter of red fibers
Few mitochondria, Lots of stored glycogen
Energy is from anaerobic metabolism
 Fatigue very quickly, Very rapid and intense contractions
Term
Intermediate fast twitch fibers
Definition
Red or pink, Diameter of the fibers in intermediate
Fast acting fibers like in white muscle
More dependent on myoglobin Have more myoglobin
Lots of capillaries, Uses aerobic metabolism
Fatigue resistant ``(they are fast acting like red muscle but need more oxygen)

Term
Fibers and microscopic structure of Smooth Muscles
Definition
Smooth spindle shaped cells with a single nucleus in the center
Organized into two layers of cells
Exhibit peristalsis
Term
Peristalsis
Definition
Alternating contraction of the two layers
Moves a substance down a tubem, EsophagusControlled by the autonomic nervous system, Lack T tubules, SR connects directly to the cell membrane, APs directly stimulate the SR to release Ca2+ Lacks striations

Term
Smooth Muscle Functions
Definition
Moving substances through body passages
Expulsion of stored substances
regulation of the size of openings (like the pupils)
Regulation of the diameter of tubes
Term
Smooth Muscles Lack Striations
Definition
No sarcomeres
Thick and thin filaments spiral down the cells length
Myosin has more actin gripping heads
Permits equal power to skeletal muscle

Term
Contraction of Smooth Muscle
Definition
Slow synchronized contractions, Coordination is by hollow cylinders called gap junctions, `Permits direct movement of AP’s between adjacent cells, Some cells act as pacemakers (set the rhythm of the contraction) Contraction is like skeletal muscle contraction Slow fatigue resistant sustained contractions, Takes 30x longer to contract than skeletal muscle
Can stay contracted for longer periods with less energy that skeletal muscle, Have low energy requirements
Most ATP is made anaerobically, Regulation of contraction is similar to skeletal muscle with both electrical and chemical stimulation
Term
Contraction of Smooth Muscle is like skeletal muscle contraction  
Definition
Actin and myosin interact
Contraction caused by intracellular calcium
ATP provides the energy
Term
Response to stretch
Definition
All muscles respond with more intense contractions when stretched
In smooth muscle stretching moves materials along a passageway
Term
Stretch-relaxation
Definition
Increased tension lasts for a short while
Smooth muscle returns to its normal tension in a few minutes, Permits an organ lined with smooth muscles to fill or slowly expand, Enables slow movement of substances through a tube

Term
Length and tension changes
Definition
Smooth muscle can stretch more that skeletal muscle
Corkscrew like nature of the myosin permits more overlap between the thick and thin filaments
Term
Length and tension changes Permits smooth muscle to:

Definition
Stretch when needed
Be thin when needed
All without making the muscle flabby when empty

Term
Hyperplasia
Definition
Smooth muscles fibers are able to divide and reproduce, Important when an increase in the size of an organ is needed, Uterus during pregnancy

   
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