Exam 2 Flashcards
What are the three types of muscles?
- Cardiac
- Skeletal
- Smooth
What is the function of muscle?
To move body and things within the body (contraction)
What is the sarcolemma?
Plasma membrane of muscle fiber
What is the sarcoplasmic reticulum?
Smooth ER of muscle cell
What are the functions of the sarcoplasmic reticulum?
Storage for fiber, calcium release control
Smooth Muscle
1. Striation and is it voluntary?
2. Shape of cells
3. Where is the nucleus located
4. What regulates it?
5. Where is it found?
- non-striated and involuntary
- spindle-shaped
- centrally located
- The autonomic nervous system (ANS)
- Found in hollow viscera, eye, attached to hairs (arrector pili)
Cardiac Muscle
1. Striation and is it voluntary?
2. Where is it found?
3. What is it controlled by?
4. Shape of cells
5. Where do the ends of the cells join?
- Straited and involuntary
- Only in the heart
- regulated by the ANS
- elongated and branching
- Intercalated disk
What is an intercalated disk?
A specialized membrane that facilitates transmission of electrical impulses
Skeletal Muscle
1. Striation and is it voluntary?
2. Nuclei (number and location)
- striated and voluntary, except for reflexes
- Multiple nuclei and off-center location
What type of muscle makes up the majority of the muscle mass in the body?
Skeletal muscle
True or false? Cardiac muscle does not branch and does not have intercalated disks. If false, which type of muscle does this refer to?
False, Smooth muscle
True or false? Skeletal muscle, is innervated by cranial and spinal nerves. If false, which muscle type does this refer to?
True
Origin
Least movable attachment, proximal and medial
Insertion
most movable attachment, distal or lateral
What brings insertions and origins together?
Contractions
Extensors
Extend/increase angle between body parts
Flexors
Flex/decrease angle between body parts
Adductors
pull limb towards median plane
Abductors
move limb away from median plane
Constrictors (sphincters)
surround circular opening, close when contracted
Dilators
surround circular opening, open when contracted (rare in mammals)
Agonist muscle
muscles promote given movement ex. biceps
Antagonist muscle
muscles inhibit movement, prevent hyperextension ex. triceps
What do red muscle fibers contain (3) and what are they used for?
- myoglobin for oxygen storage
- glycogen for glucose storage
- mitochondria for ATP production
Slow twitch muscle fibers
slow to contract, slow to fatigue. Used for endurance
Fast twitch muscle fibers
fast to contract, lose energy quickly
Are red muscle fibers fast or slow twitch? What about white muscle fibers?
red are slow-twitch
white are fast-twitch
Parallel in regards to tendons
tendon comes off ends of fibers to attach to bone ex. pec muscles
Pennate (tendons)
feather-like with central tendon, wide at the top and converges to tendon ex. biceps
Fleshy
appears to attach directly at bone, but has short (microscopic) tendons between fibers and bone. Ex. brachialis
Oblique
circular or convergent (abdomen)
What are the three layers of the connective tissue harnessing muscle?
- endomysium
- perimysium
- epimysium
What is the endomysium?
Loose connective tissue around muscle cells
What is the perimysium?
Loose connective tissue around muscle bundles (fascicles)
What is the epimysium?
regular/dense connective tissue around the whole muscle
What converges at the center or end of pennate cells?
The three layers of the harnessing muscle
What are muscle fibers composed of?
myofibrils
What are myofibrils composed of?
myofilaments
What is myosin? What does it look like?
Thick filament. Individual filaments resemble golf clubs and fit together with the heads sticking out
What is actin?
Thin filament
How does the muscle contract?
Myosin pulls on actin
Sarcomere
The arrangement of actin and myosin
How many sarcomeres are on a myofibril?
Hundreds/Thousands
Banding pattern
striations
A-band
length of myosin filament, includes overlap with actin, stains dark
I-band
actin only, no overlap with myosin, stains light
Z-line
ends of sarcomere. connects actin filaments
M-line
middle of sarcomere, connects myosin filaments
What are the 3 parts of actin?
- G-actin
- F-actin
- Tropomyosin
What part of actin are the molecules globular? How do they fit together? How many make actin filament?
G-actin, fit together like beads on a string, 2 G-actin filaments twisted around each other make actin filament
Where is tropomyosin located and what does it have on it?
Groove of actin filament (between actin strands). Has globular protein, troponin spaced along it.
What are the binding sites on actin for?
binding with myosin
What covers the binding sites so actin and myosin don’t bind?
Tropomyosin
What binds to troponin to relax tropomyosin?
Calcium
What is packed with myofibrils and is responsible for muscle contraction?
Muscle fibers
Why are the organelles pushed to the outside?
Because of the space myofibrils take up.
Terminal cisternae
enlarged sacs of the SR, located at the end of A-bands
T-tubules
On the sarcolemma, extend into cell around myofibrils
How many t-tubules between terminal cisternae? What is this structure called?
One, triad
Motor Unit
one motor neuron and all skeletal muscle fibers it innervates (synapses with)
Synapse of motor neuron with skeletal muscle fiber
connection between motor neuron and skeletal muscle fiber, allowing for communication
Where are the motor neuron cell bodies located?
ventral horns of spinal cord
Motor end plate
region of sarcolemma at the neuromuscular junction where the neuron synapses with the muscle fiber.
Synapse
Junction between two neurons
What are the four muscle shapes?
- oblique
- fleshy
- pennate
- parallel
What level does the muscle contract at?
Sarcomere (each unit contracts)
What causes striations?
A and I bands
____ band is always the same length while the ___ and ___ bands change
A, I + H
Ventral Root
Motor Neuron
In the spinal cord, all motor stuff comes out of the ___ aspect
ventral
A nerve impulse in the motor neuron travels down the ______ to the _____ ________
axon; synaptic bulb
What happens when the protein channel reaches the threshold?
It opens up the voltage gated gate and calcium enters the axon
What does the synaptic bulb do? Where is it located?
It is located at the end of the axon terminal and releases neurotransmitters
What is released when calcium enters the axon?
ACh (acetylcholine)
The nerve and the muscle ____ touch
Never touch; fluid filled gap between them
What is a synaptic cleft?
gap between nerve and muscle
Where does ACh bind to?
receptors on the sarcolemma
What is action potential?
transmission of electricity
How does action potential initiate contraction?
it causes the calcium channels to open in terminal cisternae which releases calcium into the sarcoplasm
ATP is __________ to how much the muscle contracts
directly correlated
ATP becomes ____ which is released so it can become ______
ADP; ATP again
What does anaerobic mean? What does it lead to?
No oxygen required, does not produce enough ATP and results in lactic acid buildup (less effective)
What does aerobic mean?
requires oxygen, yields more ATP (much more effective)
What does the buildup of lactic acid cause?
muscle cramping
What does creatine phosphate do?
Regenerates ADP to form ATP
What is contracture? What happens? (4 parts)
abnormal, rigor, muscle shorting in the absence of actin potentials, constant contracted muscle state without relaxation; ATP runs out and myosin heads can’t release actin, calcium is not re-sequestered into S.R. terminal cis.
What is rigor mortis?
contracture after death
When nerve impulse stops calcium is __________ into _______________.
re-sequestered; terminal cisternae
What is a muscle twitch?
Contraction of one motor unit (and all muscle fibers that neruron is attached/sends signials to)
Latent Phase
Cross-bridges (myosin & actin) are interacting, but nothing is moving, no tension
Contraction Phase
Myosin moves actin filaments closer together, muscle fibers shorten
Refractory Phase
short period where the muscle can not be stimulated right after muscle relaxes
Strong vs weak contractions
a weak contraction stimulates one muscle unit, a strong one stimulates multiple
Fatigue
Decrease in ATP and oxygen
Acetylcholine is released and received then __________ recycles it
acetylcholinesterase
What is wave summation?
The phenomenon where increased frequency of contraction leads to increased strength of contraction.
What happens when a muscle is stimulated to contract before it has relaxed?
The strength of the subsequent contraction is increased.
What occurs when the frequency of stimulation is increased past the threshold?
Individual muscle twitches become fused into a single prolonged contraction known as Tetany.
What is the Treppe (staircase effect)?
The gradual increase in muscle contraction strength when a muscle is stimulated multiple times with equal intensity, a few seconds apart, until it reaches optimal contraction strength.
Why does the Treppe effect occur?
Due to increasing calcium ion concentration in the sarcoplasm and the warming up of muscle fibers, which enhances enzyme efficiency.
How does Treppe differ from tetanus?
Treppe involves successive muscle twitches with increasing strength, while tetanus is a sustained contraction due to high-frequency stimulation.
What happens during the initial contractions of a rested muscle?
The contractions gradually increase in strength as calcium builds up in the sarcoplasm and the muscle warms up.
What do acetylcholinesterase inhibitors do? (4)
- prevent acetylcholine from being broken down
- Muscle keeps contracting, runs out of ATP
- Death often occurs due to contraction of respiratory muscle without relaxation
- Spastic muscle paralysis
What proteins are involved in cardiac contraction?
Cardiac contraction involves actin and myosin.
How does the sarcomere arrangement in cardiac muscle compare to skeletal muscle?
Cardiac muscle has the same sarcomere arrangement and contraction mechanism as skeletal muscle (sliding filament), with slight differences in sarcotubular arrangement and number of triads.
Where does the action potential originate in cardiac contractions?
The action potential originates in the heart itself.
What controls cardiac contraction?
The autonomic nervous system (ANS) controls cardiac contraction.
What is the role of Purkinje fibers in the heart?
Purkinje fibers in the heart spread the action potential very fast.
Smooth muscle contraction (3)
- Loose arrangement and interaction of action and myosin filaments
- More actin to myosin
- Actin attached to dense bodies
Acellular matrix that surrounds a relatively small number of cells is called
Chondrocytes
What are the two primary functions of synovial fluid?
lubrication and nourishment
Vascular Connective Tissue
lines the inner surface of the joint capsule but does not cover the bearing surfaces
What type of joints allow one surface to glide over another?
Synovial joints
What facilitates the gliding motion in synovial joints?
The presence of articular cartilage and synovial fluid
What encloses synovial joints?
Joint capsule
What is arthritis?
Inflammation of joint
The connection between any of the skeletons rigid component parts is known as a ______
Joint; articulations
Hypocalcemia
Lack of calcium, causes milk fever
bungarotoxin
binds irreversibly and competitively to receptor found at neuromuscular junction and causes respiratory failure and death
Botulism
inability to release acetylcholine at motor end plates; flaccid paralysis
Tetanus
TeNT absorbed by nerves and transported to spinal cord, spasmodic contractions of voluntary muscles with release of inhibitory neurotransmitters from presynaptic nerve endings, can cause fractures and lead to resp failure
What is Osteology the study of? What about arthrology?
bones; joints
What is a bone?
cellular structures in which the extracellular fluid environment of the cell is surrounded by a ridged, calcified frame
What is the medullary cavity?
the hollow space in the center of bones that stores bone marrow (principle location of blood formation)
Bones are dynamic structures capable of accommodating to different loads and stress by __
remodeling shape
What is the synovial membrane? What does it produce?
inner lining of joint capsule; synovial fluid
Axial Skeleton
skull, spine, ribs, sternum
Appendicular skeleton
appendages and the girdles that attach them
Articular cartilage
covers surface of bones when they come together to form joints
The neurocranium protects ___
the brain and openings for cranial nerve connections (brain case)
Viscerocranium protects ___
the organs of the special senses and openings for the digestive and respiratory system (bones of the face, surrounding mouth)
What are the 5 spinal locations?
- Cervical (neck)
- Thoratic (upper back)
- Lumbar (lower back)
- Sacral (above butt)
- Caudal (tail)
Transverse Process
site of muscle and ligament attachment
Transverse Foreman
Where cervical arteries come out, only seen in cervical vertebrae (blood vessels & nerves pass through)
The cranial and caudal surfaces of contiguous vertebrate have a covering of _________ cartilage
hyaline
Nucleus Pulposus
soft, gelatinous interior of intervertebral disc
Annulus Fibrosus
The fibrocartilaginous collar that supports the periphery of the disk (outer layer)
What three things does the pectoral girdle consist of?
- scapula
- clavicle
- coracoid
What does the pelvic girdle consist of? (3)
- ilium
- ischium
- pubis
Acetabulum
socket that connects hip joint and femur
What is the os coxae What 3 bones does it consist of?
hip bone; ischium, pubis, ilium
What is the ilium?
What is the ischium?
What is the pubis?
Top of pelvic girdle
Bottom of girdle
Middle of girdle
Obturator Foreman
opening found by the pubis cranially and the ischium caudally
What are the components of the thoracic limb?
Pectoral girdle
brachium
antebrachium
carpals
metacarpals
phalanges
What are the components of the pelvic limb?
pelvic girdle
thigh
crus
patella
tarsus
metatarsus
phalanges
How many metacarpal bones do humans, dogs, and cats have?
5; labeled 1 to 5 starting with thumb
Examples of even toed animals
cows, sheep, goats
Examples of odd toed animals
rhinos, tapirs, horses
Cannon Bone
Between knee and ankle, third metacarpal
Splint Bones
Alongside cannon bone
A horse has ___ digits and ___ phalanges
1 digit; 3 phalanges; walk on third (middle finger)
Fetlock
Joint between cannon bone and first phalanx (long pastern)
Pastern Bone
joint between 1st and 2nd phalanx
Compact Bone
smooth, strong
looks to be solid, not completely
on the outside of the bone
Spongy Bone
spicules of bones with osteocytes surrounded by matrix
appears spongy due to trabeculate of mineralized tissue
spaces between spicules are filled with red marrow
Epiphysis
ends of bone
diaphysis
middle of bone/shaft; contains medullary cavity
metaphysis
flared part of shaft
The epiphyseal plate is composed of _______ and represents growth in a _____________ direction
hyaline cartilage; longitudinal
Periosteum
tough fibrous membrane on the outside of the bone
Endosteum
inner membrane lining marrow cavity and spaces in spongy bone
Long Bones
stretched in one direction ex Femur
Short Bones
Equal in all dimensions ex. wrist bones
Flat Bones
thin (skull bones, ribs)
Sesamoid Bones
sesame seed shaped ex. patella
Irregular Bones
No definite shape (vertebrate)
Pneumatic Bones
Hollow (sinuses)
Compact bone has ____, while spongy bone has ___
osteons; trabeculae
Where is red marrow found in young vs adult animals? What does it do?
young: medullary cavity
adult: spaces of spongey bone
active in blood formation
What is yellow marrow?
fatty, replaces red marrow in the marrow cavity as the animal matures
Osteons
Structural unit of compact bone, cylindrical
Features of Osteons (3)
- circumferential lamellae
- canaliculi
- central (haversian) canals
Circumferential lamellae
layers of bone matrix that surround entire bone
Canaliculi
connect lacunae/osteocytes
Lacunae
small spaces within bone matrix to protect osteocytes
Central (haversian) canal
In each osteon, contains blood vessels and nerves
Perforating Canals
connect central canals or marrow cavity to outside of bone (contain blood vessels & nerves)
- Osteoblasts
- Osteocytes
- Osteoclasts
- young, actively depositing matrix, new bone
- less active once surrounded by hard matrix
- bone destroyers
Hydroxyapatite
Formation of bone, depositing calcium and phosphate
Calcification
Depositing calcium phosphate in tissues to make them hard, can be abnormal if occurs in soft tissue
Bones are __% water, __ % minerals, and __ % organic
25, 45, 30
Ossification center begins as ___________ move into tissue
osteoblasts
Endochondral
base layer of cartilage, acts as scaffolding, growth in length
Zone of Cartilage Proliferation
nearest epiphysis
dividing cartilage cells
nearest diaphysis: lined in columns
Zone of Calcification
- zone of hypertrophy: chondrocytes swell and die
- zone of calcification: calcium salts deposited
Osteoblasts can form from inner layers of _________ and ________ to deposit new bone
periosteum, endosteum
Epiphyseal Fracture
Fracture in growth plate, damage growth
Communuted Fracture
multiple pieces
Greenstick Fracture
often occurs in young bones, break halfway through
Compound fracture
break in skin, lead to infection of blood or bone
Osteoblasts and osteoclasts work together to move ______ around
bone matrix
Simple Fracture
No break in skin
Steps in healing fracture (7)
- bone breaks
- immobilize fracture/appose ends
- new blood vessels enter
- C.T. enters and fibrous C.T. bridges gap
- soft callus of hyaline cartilage forms
- hard callus of bone replaces hyaline cartilage
- remodeling by osteoclasts to reform marrow cavity and smooth bumps
What are the 4 types of stressors that can injure bone? What does each mean?
- Compression: chronically, bones become short and thick
- Tension: chronically, long, thin
- Shear Force: not chronic, acute, opposing forces
- Torsion: chronic, bone bends
Why is calcium important? (4)
- muscle contraction
- action potential of cardiac muscle
- enzyme cofactor
- blood coagulation
PTH (parathyroid hormone)
When is it released and what does it do?
releases when blood calcium is low
it increased bone respiration, increases kidney resorption of calcium, and stimulates kidney to convert vit D to active form
What is Vitamin D? When is it released and what does it do?
cholecalciferol
released due to low blood calcium
increases intestinal calcium absorption and kidney resorption
Calcitonin
What is it released and what does it do?
released due to high blood calcium
inhibits bone resorption and increases urinary excretion of calcium
