X A&P - Chp 8 - The Muscular System Flashcards
3 types of Muscle
Smooth
Cardiac
Skeletal
Smooth muscle
- walls of hollow body organs
- contracts involuntarily
- produces peristalsis
- can regulate diameter of an opening
- tapered at end
- single central nucleus
- no striations
Cardiac Muscle
- hearts wall
- creates pulsing action of heart
- Striated
- one nucleus per cell
- branching interconnections
- electric impulse travel rapidly through them
Intercalated discs
membrane between cardiac muscle cells (show as dark lines) allow electric impulses
Skeletal Muscle
- appear heavily striated
- long and cylindrical cells
- multiple nuclei per cell
- attached to bone and produce movement at joints
Skeletal Muscle ? % of body weight
40%
largest amount of body’s muscle tissue
Primary functions of skeletal muscles
- movement of skeleton
- Maintenance of posture
- Generation of heat (shivering)
Fascilcles
bunch of muscle fibers
Endomysium
connective tissue around individual fibers in fascicles
Perimysium
connective tissue encasing each fascicle
Epimysium
connective tissue encasing entire muscle
innermost layer of the Deep Fascia
Neuromuscular Junction
point where nerve contacts muscle cell
Acetylcholine (ACh)
a nuerotransmitter
Motor end plate
muscle cell’s receiving membrane
?????
Difference btwn Motor end plate and Neuromuscular Junction
Action Potential
spreading wave of electric current.
Contractility
muscle fiber’s capacity to undergo shortening, becoming thicker.
Proteins that make up muscle fiber
Actin - thin and light
Myosin - thick and dark
Sarcomere
contracting sub-unit of skeletal muscle
What triggers Myosin heads to move?
ATP
What needed to allow crossbridge to form between actin and myosin
Calcium
Calcium stored where
Sarcoplasmic Reticulum
Troponin and Tropomyosin cover sites on actin where cross bridges form until
Calcium attaches to troponin and they move aside allowing access to bonding sties
Calcium released into cytoplasm when
muscle is stimulated by nerve cell
Steps of muscle contraction
1) ACh released from nueron to synaptic cleft at NMJ
2) ACh binds to muscles motor end plate and produces action potential
3) Action Potential travels to SReticulum
4) SR releases Ca into cytoplasm
5) Ca shifts troponin and tropomyosin so binding sites on actin are exposed
6) Myosin heads bond to Actin forming cross-bridges
7) using stored energy, Myosin heads pull filaments together within sarcomere (cell shortens)
8) New ATP is used to detach myosin heads and move back for another stroke
9) Muscle relaxes when stimulation ends and Ca pumped back into SR.
Myoglobin
stores O2 in muscles, similar to hemoglobin in blood
Glocogen
storage form of glucose
Types of Muscle Contractions
Isotonic
Isometric
Isotonic contractoin
tension remains the same
movement
Isometretic
no movement
increase in tension
Tendon joins
Muscle to Bone (achilles tendon)
Ligament
Bone to Bone
Agonist
muscle to performs movemetn
Antagonist
muscle that produces the opposite movement to the Agonist
Synergists
helping muscles. work w Agonist to complete movement
Muscular Disorders
Spasm
Cramps
Atrophy
Muscular Injuries
Strains
Sprains
Purpose of Bones
- Blood formation
- Protection
- store minerals (Ca)
Where Marrow is made when young
Spongy Bone
Where marrow made in adults
in flat bones of skull, sternum, Ilium crest, ribs
Hematophoesis
Creation of blood
Types of muscles
- smooth
- cardiac
- skeletal
Smooth muscle
see pic
- Involuntary
- tapered cells
- single nucleus
- no striations
Stimulated by nerve impulse, hormones, stretching
stomach, intestines, gut, arteries, uterus, stomach, respiratory passage, blood vessels
Can dilate and constrict veins
Cardiac Muscle (see pic)
- branching interconnections (allow electric impulse to travel)
- single nucleus
- striated
- membranes are interkolated discs
- involuntary
Skeletal Muscle
- attached to bone, muscles or skin
- voluntary
- long, cylindrical
- multiple nuclei per cell
- Heavily striated
Diaphragm only skeletal muscle under Involuntary control
When is Skeletal muscle involuntary
Shivering
Spasm/Twitches
Seizure
Myofibrils
Actin - thin, light
Myosin - thick, dark
Propreoception
muscle memory
Skeletal Muscle functions
- movement
- posture
- heat generation
Tendons
Muscle to bone
Ligament
bone to bone
Motor Unis
single neuron and all the muscle fibers it stimulates
Neuromuscular Junction (NMJ)
where neuron meets muscle. whole setup of axon, muscle, synapse
Motor Endplate
area on muscle where muscle receives electric current
Acetylcholine (ACH)
Neurotransmitter which stimulates all skeletal muscle to move
Excitability
any muscle that has an action potential
nervous and muscle tissue only
How does muscle contract
calcium released and Myosin pulls actin towards itself.
Role of Calcium
- released when nerve fiber stimulates muscle cell
- attaches to proteins blocking receptor sites
- allows cross-bridge to form btwn Actin/Myosin
- returns to Sarcoplasmin reticulum
Energy Sources
- oxygen
- Glucose
Compounds in muscle that store
Myoglobin - oxygen
Glocogen - ready source of glucose. (stored in liver/muscle)
Creatine Phosphate - Phosphorus
Need Phosphorous to make ATP
Muscles have creatine phosphate to supply the phospherous
Benefits of Excercise
- improved balance, joint flex
- increase muscle size (burns more calories in resting)
- strengthened heart muscle
- Improved breathing
- weight control
- stronger bones
Types of Muscle Contractions
ISOTONIC - weight lifting
no change in tension
muscle length shortens
movement
ISOMETRIC- keigels
change in tension
muscle length unchanged
no movement
Origin
muscle attached to fixed part of skeleton
Insertion
muscle attached to more movable part of skeleton
Muscles
Rectus
Obliques
Rectus - straight lines
Oblique - diagonal
Number of attachment points
Biceps - 2
Triceps - 3
Muscle Actions
flexors, levators, erector,
Calve Muscles
Gastrocnemus
attached to Achilles tendon
signs of DVT
Deep Vein Thrombosis
warmth, redness, tenderness
Vastu Lateralus
side thigh
Rectus Femoris
front thigh
Injection Sites
Deltoid Rectus Femoris vastus lateralis (side thigh) ventrogluteal or gluteus medius dorsogluteal muscle
2 holes on top of diapragm
Hiatus
Esophogus and Aorta/Venacava
