Chapter 8- Muscular System Flashcards
List three types of muscle
Smooth
Skeletal
Cardiac
Skeletal muscle
Controlled by conscious mind, moves the skeleton
Attached to bone
striations
Cell shape long and cylindrical
multiple nucleus
Needs a functional nerve supply to contract
function- moves the whole body and glycogen storage
Up to 1/2 the body weight
Rapid contractions
Cardiac muscle
Found only in the heart
cell shape - Branched
nucleus - usually single, central
has intercalculate discs
striated
does not need nerve supply
pumps blood through body
Smooth muscle
Carries out unconscious, internal movements of the body
All over the body
No striations
Single cell
Cell shaped- spindle
Has cell to cell attachments
Involuntary and autorhythmic
helps stuff moves in body.
Nerves not necessary for function
Describe the structure and function of tendons
Fibrous connective tissue that attaches muscle to bone
Describe the structure and function of aponeuroses
Attach to muscles or bones by broad sheets of fibrous tissue
Describe the structure and function of ligaments
Bands of connective tissue present in and around synovial joints. Join bones to bones
Prime mover
The muscle that contracts and directly produces a result
(Agonist)
Antagonist
A muscle that contracts and opposes the prime mover
Synergist
A muscle that contracts at the same time as a prime mover and assists it in carrying out a motion
Fixator muscles
Muscles that stabilize joints and allow movements to take place
Abdominal muscles
Support abdominal organs
Help flex the back
Participate in defecation, urination, birth, vomiting, regurgitation
Have a role in respiration
Arranged in layers
- external (less important)-abdominal oblique
-internal (less important) abdominal oblique
-rectus - abdominis
-transverse abdominis
Come together at the linea alba (white line)
Thoracic limb muscles
Function in locomotion
Less important
Deltoid muscle.
Supraspinatus muscle.
Infraspinatus muscle.
Teres minor muscle.
Teres major muscle.
Subscapularis muscle.
Articularis humeri muscle.
Coracobrachialis muscle.
pelvic limb muscles
Functions mostly locomotion
Microscopic anatomy of skeletal muscle
Large cells - not wide but long
multi-nucleated - located at edge of cell just beneath sarcolemma
Made up of lengthwise myofibrils
many mitochondria in extensive network of sarcoplasmic reticulum and transverse tubules
Microscopic anatomy of smooth muscle
Small and spindle-shaped
Single nucleus
Smooth, homogenous appearance
-myosin and actin not arranged in parallel myofibrils
Myosin and actin criss-cross the cell and are attached at both ends to dens bodies
Microscopic anatomy of cardiac
Striated
smaller than skeletal
Single nucleus per skill
securely attached end to end to form intricate, branching networks of cells
-attachment sites are called intercalated discs
List the components and functions of neuromuscular junctions
Site where ends of motor nerve fibers connect to muscle fiber
Synaptic vesicles at the nerve fiber contain nerve acetylcholine
-Motor neuron (axon)
-Muscle fiber (receptor site)
-Synaptic space - cleft
- acetylcholine
(lots of mitochondria)
List and describe the roles of connective tissue in muscles
There are three layers of connective tissue: epimysium, perimysium, and endomysium. Skeletal muscle fibers are organized into groups called fascicles. Blood vessels and nerves enter the connective tissue and branch in the cell. Muscles attach to bones directly or through tendons or aponeuroses.
What happens during muscle contraction and relaxation
Relaxed muscles have myosin and actin filaments that overlap slightly
When stimulated to contract, cross bridges on myosin filaments slide back and forth
actin fillaments on both sides are pulled toward the center of the myosin fillaments
This shortens the sarcomere
Shortening of all end-to-end sarcomeres causes muscle to contract
Differentiate between visceral smooth muscle and multi-unit smooth muscle
Visceral smooth muscle -
-large sheets of cell walls in some hollow organs
multi-unit smooth muscle-
-small, discrete groups of cells
Muscle cells
Fibrous cells designed for contraction
Also called muscle fibers
Fiber composition- myosin and actin
microfilaments slide over one another
Very large
Skeletal - multi-nucleated
Network of sarcoplasmic reticulum
Muscle functions
Provide motion
Maintain posture
Heat the body
Muscle characteristics
Excitable
Contractible
Extendable
Elastic
Gross anatomy of skeletal tissue
Muscle fibers
Fibrous connective tissue
Belly
Tendon (fibrous tissue that connects muscle to bone)
Periosteum
Tendon
Fibrous connective tissue that connects muscle to bone