|
Home > Preview
The flashcards below were created by user
darlene.m.nelson
on FreezingBlue Flashcards.
-
Muscles
- one of the 4 tissues
- 3 types:
- - cardiac
- - visceral (smooth)
- - skeletal (striated)
-
Skeletal muscle
- voluntary striated muscle
- under concious control
- associated with the skeleton
-
Gross anatomy of skeletal muscle
- belly - thick central portion
- tendon - attachment to th bone
- aponeurosis - connects muscle to muscle, e.g. linea alba
-
Tendon
muscle to bone attachment
-
Ligament
bone to bone attachement
-
Muscle attachments
- tendon is a continuation of the periosteum of the bone
- - dense irregular CT (periosteum) into dense regular (CT) (start of tendon) into muscle
- - continuous tissue
- eg biceps originates at shoulder/clavicle, inserts at radius/ulna
- eg trapezius originates at spinal process, inserts at humerus
-
Origin
stable end of muscle attachment
-
Insertion
movement end of muscle attachment
-
Muscle actions
- prime movers (agonists)
- - directly produce desired movement, eg biceps to flex elbow
- antagonists
- - directly opposes motion of agonist, eg triceps to extend elbow
- synergists
- - assist the action of the prime mover
- - give nuance, subtlety in movements
- fixator
- - stabilize joints to allow movement to take place
- - moderates movement
- every bone has paired muscles
- if no synergists, fixators then we would move like toy soldiers
- - requires brain development
-
Naming muscles
- action - flexor, extensor, adductor, abductor
- shape - deltoids (triangle), trapezious (trapezoid)
- location - brachii (upper arm), femori (upper leg), carpi (wrist)
- fiber direction - rectus (straight), oblique (at an angle)
- number of heads (cep) at origin - biceps, triceps, quadricecps
- attachment sites - sternocephalicus
-
Cutaneous muscles
- superficial muscles
- 1st layer just under the skin
- can feel these through the skin
- horses well-developed; humans not
- muscles of the head and neck:
- - masseter
- - splenius
- - trapezius
- - brachiocephalicus
- - sternocephalicus
-
Masseter
- closes jaw
- importance in dogs - eosinophilic myositis - masseter painful, won't open mouth
-
-
Trapezius
raises the head
-
Brachiocephalicus
- extends neck
- pulls forelimb forward
-
sternocephalicus
lowers the head
-
Abdominal muscles
- support the abdominal organs
- flex & extend the spine
- provide for the abdominal press
- - urination
- - defecation
- - parturition
- assist in respiration
- - if diaphragm fails, you can use abdominal muscles to breathe for a little while
- arranged in layers
- in people, they allow you to stay upright
- animals aren't as developed (extremely thin) as they don't use them
- linea alba doesn't bleed; muscles will, so surgically want to stay on linea alba
-
Abdominal muscle layers
- external abdominal oblique - fibers @ angle
- internal abdominal oblique
- rectus abdominus
- transversus abdominus
-
Thoracic limb muscle
- each component of thoracic limb skeleton has muscles associated
- superficial muscles of the shoulder
- - latissimus dorsi
- - pectoralis
- - deltoid
- muscles of the brachium
- - biceps brachii
- - triceps brachii
- muscles of the distal thoracic limbs
- - extensor carpi radialis
- - deep digital flexor
-
Latissimus dorsi
- spines of the vertebrae to humerus
- flexes the shoulder - pulls the leg back
-
Pectoralis
- huge in horses
- superficial and deep
- sternum to humerus
- adduction - holds legs in (together)
-
Deltiod
- lateral scapula to humerus
- abducts (less in animal than human) and flexes (pulls it back) shoulders
-
Biceps brachii
- 2 heads
- distal scapula to proximal raduis
- flexion of the elbow
-
Triceps brachii
- 3 heads
- distal scapula to proximal humerus - olecranon process
- extends the elbow
-
Extensor carpi radialis
extend the carpus
-
Deep digital flexor
flexes the paw
-
Pelvic limb muscles
- muscles that move the hip
- - gluteals
- - hamstring
- muscles that move the stifle
- - quadriceps
- muscles of the lower hind leg
- - gastrocnemius
- - tibialis
-
Gluteals
- pelvis (ilium mostly) to trochanters
- think of rump roast
- humans - butt muscles
- extend the hip
-
Hamstrings
- semimembranous - half muscle, half membrane
- semitendinous
- biceps femoris - 2 headed on femur; think of ham for baking
- attaches with membrane instead of tendon
- caudal thigh
- extend hip
- flex stifle
-
Quadriceps
- big muscles
- front of leg
- one muscle - one tendon of insertion
- 4 heads:
- - rectus femoris - large straight muscle in front
- - vastus laterlis
- - vastus medius
- - vastus intermedius
- stifle extensors
- largest muscle in the body
-
Gastrocnemius
- caudal - back of tibia
- achilles tendon
- tibia to calcaneous
- extends tarsus (hock)
-
Tibialis
- cranial
- tibia
- flexes the tarsus (hock) - toe up to sky
-
Muscles of respiration
- inspiration - increases the size of the thorax
- expiration - decreases the size of the thorax
- inspiratory muscles
- - diaphragm
- - external intercostal muscles (between ribs ; think of BBQ ribs)
- expiratory muscles
- - internal intercostal muscles
- - pennate - like feathers
-
Skeletal muscle cells
- cells - muscle fibers
- cell membrane - sarcolemma (same as plasmalemma, different name)
- multinucleate
- myofibrils
- - inside myofibers
- - composed of protein filaments (actin & myosin)
- sarcoplasmic reticulum - same as ER
- transverse tubules (or T-tubes)
- - channels for ion exchange
- - calcium is main ion
- skeletal muscle cells must be insulated from each other or all would fire at once (no fine movement)
-
Sarcomere
- contractile unit of striated muscle
- racheting action
-
Neuromuscular junction
- skeletal muscles require nerve impulses to contract
- neuromuscular junction or synapse - site where nerve fibers connect to muscle fibers
-
Motor unit
one nerve fiber and all of the muscle fibers (cells) it innervates
-
Muscle physiology
- nerve impulse causes the release of acetylcholine
- acetylcholine binds to the sarcolemma
- calcuim (Ca) is released into the sarcoplasm and diffuses into the myofibrils
- Ca binds to the myosin & contraction begins
- contraction & relaxation of the muscle require ATP
- muscle needs Na, K, H20, Ca to work
-
Characteristics of muscle contraction
- all or nothing - each fiber either contracts completely or not at all
- allows for a few fibers within a muscle to contract allowing for fine motor movement
- controlled by the nervous system which learns how to control the muscles as baby
- "muscle memory"
- - once your muscles learn how to do something, they won't forget unless injured
- - in injury other muscles will compensate
- - even after healed will still use other muscles
- - physical therapy retrains muscles to work correctly
-
Muscle contraction
- twitch contraction - individual fiber contraction
- 3 phases:
- - latent
- -- brief hesitation between stimulus & actual contraction (10 ms)
- -- time it takes for synaptic vesicles to release & bind
- - contracting
- -- movement within the sarcomere (40 ms)
- - relaxation
- -- 50 ms (as long to relax as to contract)
-
-
Cardiac muscle
- found only in the heart
- involuntary, striated muscle
- branched
- uninucleate
- smaller than skeletal muscle cells
- intercalated discs
- - desmosomes & gap junctions
- contraction occurs same way as skeletal muscle
-
Cardiac muscle contraction
- autorhythmicity - each cell contracts without stimulation
- when cells touch, synchronize rate to fastest cell's rhythm
- wavelike contraction
- internal impulse conduction system, sino-atrial node, regulates heart rate
- SA node = pacemaker
- injury
- - blunt trauma to chest - disrupts SA node - cells start beating individually
- - HBC - 12-124 hours later, have arrhythmias - bruises develop & disrupt rhythm
- cardiac muscle cells cannot be insulated or won't work
-
Innervation of the heart
- modifies the activity of the heart
- autonomic nervous system
- - parasympathetic
- -- slows the heart rate
- -- eg eat a big meal, vagus nerve increases blood flow to gut
- - sympathetic
- -- increases heart rate
- -- fight or flight
- -- eg scary music will make you react
-
Smooth muscle
- located in the walls of hollow organs and blood vessels
- not striated
- - still has actin & myosin, but arranged differently
- involuntary
- uninucleate
- visceral smooth muscle - large sheets in the walls of hollow organs
- multiunit smooth muscle - small discrete groups of cells
- dense bodies
- - similar to Z lines
- - allow attachment of actin & myosin
-
Physiology of smooth muscle
- peristalsis - contracts in slow, rhythmic waves
- autorhythmic - so don't have to think about moving food through GI tract
- responds to stretching - eg eating large meal
- responds to stimulation from the autonomic nervous system
- - sympathetic - decreases contraction - eg don't want to have to go to bathroom during flight response
- - parasympathetic - increases contraction - to move food through GI tract
-
Borborgymus
gurgling noise in stomach
-
Multiunit smooth muscle
- tiny groups of cells - 3/4/5 cells
- small & delicate
- walls of blood vessels & bronchii
- pupil of the eye - when lie, autonomic NS causes this to change
- arrector pili - hackles up
- not autorhythmic - not constantly going
- under autonomic control
- - not being chased by tigers, just Dr. K (stress due to finals)
- - yoga, meditation can help
|
|
Get the free mobile app
Take the Quiz
Learn more
Learn more