A&P Chapter 8(Muscle)

Cutaneous muscle

"skin muscles"; thin muscles in the connective tissue beneath the skin, sever to "twitch" the skin

What is the difference between a tendon and an aponeurosis?

A tendon is a band of fibrous connective tissue that attaches muscle to bone. An aponeuroses is a broad sheet of fibrous connective tissue.

Involuntary striated muscle

Cardiac muscle

Describe a cardiac muscle cell in terms of size, shape, number of nuclei, and appearance under the microscope.

Cardiac muscle is striated but smaller than skeletal muscle cells. These muscles have only one nucleus per cell. The cardiac muscle cells are longer than they are wide and have multiple branches. They are attached to each other by intercalated discs.

What are intercalated discs and why are they important to the functioning of cardiac muscle?

Intercalated discs are the attachments of the end of one cardiac muscle cell to the end of another cardiac muscle cell. They secure the cells together and transmit impulses from cell to cell, thus coordinating the contraction of large groups of cells.

Reptiles that are able to raise body temperature via metabolic processes

Leatherback sea turtles--generate body heat internally Pythons--elevate temperature via muscle contraction when incubating eggs

Describe a skeletal muscle cell in terms of cell size, shape, number of nuclei, and appearance under the microscope.

Skeletal muscle cells are large and long and have multiple nuclei. Under a microscope the cells appear striated or striped.

Transverse tubule(t-tubule)

T Tubules: system of tubules in a skeleal muscle cell that extend from the sarcolemma into the depths of the cell. Help carry an impulse caused by nerve stimulation into the depths of the cell.

Expiratory muscle

a muscle whose action is to decrease the size of the thoracic cavity; this squeezes air out of the lungs, thereby producing expiration

Skeletal muscle fiber

a skeletal muscle cell. because of their long, thin fiberlike appearance, skeletal muscle cells are often called skeletal muscle fibers. can be several inches long. Large fibers may have 100 or more nuclei per cell all located at the edge of the cell just beneath the sarcolemma. One skeletal muscle fiber is made up of hundreds or more small myofibrils packed together lengthwise.

tail autonomy

abililty of lizards and salamanders to drop tails when being attacked. tail continues to wiggle. little/no blood loss, tail can regenerate. new tail is usually smaller and stiffer than the original.

where is smooth muscle found

all of body, but not in distinct structures like skeletal muscles and the heart

quadrate bones

allow the snake mouth to open very wide

during elevation of wing, why do the flight feathers separate slightly from each other

allowing air to pass through, creating less resistance, allowing wing to move more easily

pectoral crest

allows for attachment of wing muscles

what do skeletal muscle cells look like under a microscope

alternating, crosswise, dark and light bands run the length of each cell

cardiac nerve supply

although it is not needed to initiate the contractions of cardiac muscle, the heart does have a nerve supply that can modify its activity. nerves to the heart are from both sympathetic and parasympathetic systems

Reptile skulls--two types

anapsid diapsid

extensor carpi radialis is a muscle of teh

antebrachium

gluteal and hamstring muscle group

are extensor muscles of the hip help propel the body forward by extending the hip joint.

drink patches

areas of increased permeability, usually present on the ventral surface

abdominal muscles are involved in

back extension

why are snake skulls extremely mobile

because the mandibular symphysis is not fused but rather is connected by ligaments. the flexible connection of the rostral mandibles allows the jaws to move independently of one another and literally "walk" forward when prey is ingested.

Why are the oblique muscle called oblique

because their fibers run in an "oblique"(slanting)direction to the long axis of the body and opposite to each other.

three hamstring muscles

biceps femoris semimembranosus muscle tendinosus muscle

what gives birds greater control in manipulating food and increases their gape?

birds can move their upper and lower bills independently

describe avian vertebra

birds have few vertebrae in the three central regions, but more vertebrae in the cervical and coccygeal areas allowing greater mobility of neck and tail

osteoderms

bony plates within dermis of some reptiles. provide protection

catabolism

breakdown of nutrient molecules, two main compounds involved are glucose and oxygen

Aponeuroses

broad sheet of fibrous connective tissue that attaches certain muscles to bones or to other muscles

latissimus dorsi

broad, triangular muscle that extends from the spinal column down to its insertion on the humerus

number of vertebrae in amphibians

caecilians up to 250 salamaders 30-100 anurans 6-9

describe the ribs in reptiles

caecilians: well developed salamanders: poorly developed anurians: well developed, ossified sternum

Sarcolemma

cell membrane of a muscle cell

shed cycle is initiated by

cellular replication in epidermis followed by secretion of lymph containing enzymes between the old and new epidermal layers

ectothermic

cold blooded unable to generate body heat internally, therefore body temp is dependent on environmental temperatures

describe the skull of caecilians

compact, well-ossified skulls. dentition is well developed.

creatine phosphate

compound in the muscle fiber that converts ADP back to ATP

wings

connected to the body by forming a joint with the shoulder girdle. Highly flexible joint allowing rotation of the wing in several planes

synaptic vesicles

contain the chemical neurotransmitter acetylcholine

avian pectoral girdle

coracoids, scapulas, clavicles

what's the orientation of fibers of the internal abdominal oblique muscle

cranioventral

which compound provides energy to convert adenosine diphosphate back to adenosine triphosphate

creatine phosphate

Sarcoplasm

cytoplasm of a muscle cell

structures that are attachment sites for actin and myosin in smooth muscle cells

dense bodies

dermis of reptiles is made up of

dense connective tissue blood andlymph vessels nerves chromatophores

anapsid skull

do not have temporal openings

bony shell of chelonians is made up of

dorsal carapace and ventral plastron

in birds, femur=

drumstick

Four common characteristics of muscle cells

excitability contactability extensibility elasticity

gluteal muscles

extend from the bones of the pelvis down to the trochanters of the femur

List the abdominal muscles from outside in:

external abdominal oblique internal abdominal oblique rectus abdominis transversus abdominis **the left and right parts of each muscle come together on the ventral midline at the linea alba

Perimysium

fibrous connective tissue layer in skeletal muscle that surrounds groups of muscle fibers and binds them into groups called fascicles

alula bone

first finger of avian wing--originates from wrist and carries the alula feathers which are important for steering

________________ stabilize joints to allow other movements to take place

fixators

lactate

formed as result of anaerobic metabolism. decreases the ph of the blood and tissues and is metabolized slowly by reptiles. thus, reptiles are unable to sustain physical activity and are capable of only short bursts of motion

visceral smooth muscle(viscera)

found in the walls of many internal soft organs. muscle cells are linked to form large sheets in the walls of the organs. fine movement is not possible with viscera---rather large, rhythmic waves of contraction.

how many toes do anurans and salamanders typically have

four toes on the pectoral limbs five toes on hindlimbs

most species of birds have how many toes

four(can be 2-4)

pgostyle

fusion of coccygeal vertebra that supports the tail feathers.

Which muscle has the achilles tendon on its distal end

gastrocnemius

Muscle fibers can store glucose in the form of

glycogen

sinoatrial node

group of specialized cardiac muscle cells in the wall of the right atrium of the heart that act as the heart's pacemaker. The impulse that starts the heartbeat is in initiated in the SA node.

biceps brachii muscle

has two proximal head attachments and extends from the distal end of the scapula to the proximal end of the radius. Flexes the elbow joint when it contracts.

behavioral thermoregulation

herptiles maintain temperature precisely according to metabolic need. (sun/shade)

why does uterus not contract with stretching?

hormones such as progesterone inhibit contraction. When the level of progesterone drops dramatically, it is time to give birth

the number of muscle fibers per nerve fiber determines what

how small a movement will result from a nerve stimulus

pelvic girdle of amphibians consists of the

ilium, ischium, pubis

urostyle

in anurans, the vertebra are fused, and the last caudal vertebra is called the urostyle

sternum

in birds, this is the place of origin of the flight muscles.

Intramuscular

in the muscle

muscles of amphibian and reptile

incapable of sustained aerobic metabolisma and switch quickly to anaerobic metabolism with prolonged physical exertion

All or nothing principle

individual muscle fiber either contracts completely when receives a nerve impulse or not at all

parasympathetic fibers in heart

inhibit cardiac function causing it to beat more slowly and with less force when body is relaxed and resting

two sets of muscles that aid in the process of expiration are

internal intercostal muscles and abdominal muscles

explain process of expiration

internal intercostal muscles contract, they rotate the ribs backward, which decreases the size of the thorax and pushes air out of the lungs. When abdominal muscles contract, they push the abdominal organs against the caudal side of the diaphragm. This pushes the diaphragm back into its full dome shape and decreases the size of the thorax

pelvic limb muscles

involved mostly in locomotion

Adductor muscle

inward movement---help keep the front legs under the animal and prevent them from splaying out to the sides

pectoral girdle of anuris

is completely ossified. made up of scapula, clavicle, and coracoid

incomplete glucose breakdown that occurs during anaerobic metabolism can cause a byproduct called

lactic acid

keel

large bony ridge to which the muscles attach **flightless birds do not have a keel**

A band

large, dark bands in a skeletal muscle fiber that alternate with lighter I bands to give striped appearance to muscle fibers under a microscope. composed of thick filaments of myosin.

I band

large, light bands in a skeletal muscle fiber that alternate with the darker A bands to give a striped appearance to skeletal muscle fibers under a microscope. I bands are composed of thin filaments of the contractile protein actin

list the superficial muscles of the shoulder region

latissimus dorsi pectoral deltoid

hatching muscle

located on dorsal side of chick's head, develops during embryonic stage and is needed to help a chick break out of its shell. It is largest a day or two prior to hatching, then atrophies after hatching

main function of thoracic limb skeletal muscle

locomotion

which is the most powerful of the chewing muscles

masseter--main action is to close the jaw

Masseter is a muscle of __________________

mastication

astragulus and calcaneum

metatarsal bones in anurans

bottom of a bird foot is called

metatarsal pad

agonist(prime mover)

muscle or muscle group that directly produces desired movement

anaerobic metabolism

not as efficient as aerobic. results in lactic acid formation as a byproduct of incomplete glucose breakdown. lactic acid can accumulate in muscle tissue causing discomfort.

what is the purpose of nerve supply for visceral muscle

not to initiate contractions but to modify them. Like cardiac, consists of sympathetic and parasympathetic systems but with opposite effects. Sympathetic decreases muscle activity. parasympathetic increases it.

motor unit

one nerve fiber and all the muscle fibers that it innervates

anisodactyl

one toe faces the rear, and the rest face forward

anisodactyl

one toe points backward and other toes face forward

Viscera

organs

Aerobic metabolism

oxygen-consuming metabolism. Type of metabolism in the muscle in which the supply of available oxygen is sufficient to keep up with the energy needs of muscle fibers. Extracts the maximum amount of energy from glucose molecules.

larger, more superficial muscle that inserts on the underside of the humerus. when it contracts, it depresses the wing, causing the downstroke

pectoralis

which is the muscle of choice for administering intramuscular injections into birds

pectoralis

avian skeleton

pg 511

chromatophores

pigment containing cells--allow some species to change skin color

synsacrum

plate formed with first few coccygeal vertebrae that is light, strong and fuses with the pelvis to provide a stiff framework for support of the legs acts as a shock absorber to protect the legs and backbone from injury when a bird lands

gastrocnemius muscle

powerful extensor muscle of the hock.

pectoral girdle of salamanders consists of

precoracoid, coracoid, scapula--all are cartilaginous and are ossified only at the point where they articulate with the humerus

unique feature of repitilian axial skeletal

presence of a single occipital condyle that forms the articulation between the skull and spine

Differentiate between prime mover, antagonist, synergist, and fixator muscles

prime mover(agonist): a muscle or muscle group that directly produces desired movement antagonist: directly opposes the action of agonist synergist: contacts at the same time as an agonist and assists it in carrying out action Fixator: stabilize joints to allow other movements to take place

uncinate process

projection from avian ribs that overlaps the adjoining rear rib to strengthen the rib cage. (exception: penguins thoracic vertebra are less rigid because they require flexibility to swim)

sclerotic ring

protective bony plates bordering the large eye sockets of the avian skull

avian pelvic girdle

provides rigid framework for support of legs. Each side is made up of three bones that join where the leg attaches to the body: ileum, ischium, pubis

preferred optimal temperature zone(potz)

range of temperatures at which the animal can perform all necessary metabolic functions

describe the spine of reptiles

regions of spine are presacral, sacral, and caudal

which phase lasts longest in a twitch contraction

relaxation

acetylcholene

released by synaptic vesicles into the synaptic space

Origin of transversus abdominus muscle

ribs and sternum

in a healthy heart, where does the pace at which cardiac muscle cells contract originate

right atrium, specifically the sinoatrial node

beta keratin

rigid and is found in the scales

spectacle

scales covering eyelid of snake

zygodactyl

second and third toes face forward and first and fourth toe are directed backward

ecdysis

shedding of the skin

Linea alba

sheet of fibrous connective tissue that connects the abdominal muscles from each side on the ventral midline

twitch contraction

single muscle fiber contraction **twitches of individual muscle fibers are stimulated out of phase with each other which allows for smooth contraction

tarsometatarsus

single, elongated bone that forms the ankle of the bird

which cells have multiple nuclei

skeletal

3 types of muscle making up the muscular system

skeletal cardiac smooth

patagium

skin extending from the shoulder to the wrist that is lightly vascularized and possess a ligament that runs along its cranial edge. provides elasticity to the wing and assists in the aerodynamics of flight. If patagium is damaged, bird may be grounded permanently

avian axial skeleton

skull, vertebral column, sternum

smooth muscle cells shape

small and spindle shaped with single nucleus in the center

Synaptic space

small space existing between the end of the nerve fiber and the sarcolemma of the muscle fiber.

shivering

small spasmodic muscle contractions to produce heat

multi-unit smooth muscle

small/delicate. made up of individual smooth muscle cells or small groups of cells. found in areas where small contractions are needed such as iris and walls of small blood vessels. contractions are not automatic--require impulses from autonomic nerves to contract

cardiac muscle cells

smaller than skeletal muscle cells--have only one nucleus per cell. longer than they are wide and have multiple branches. Securely attached to each other end to end to form intricate, branching networks of cells.

muscles of snakes

snakes have well-developed epaxial muscles that attach the ventral scutes to teh ends of the ribs

alpha keratin

softer and more flexible in the interscaler skin

sympathetic fibers in heart

stimulate the heart to beat harder and faster as part of fight or flight response

Components of integument of reptiles

subcutaneous space(limited) dermis epidermis

function of abdominal skeletal muscles

support the abdominal organs; flex the back and participate in various functions involving straining; involved in respiration

smaller, deeper flight muscle that turns into a tendon that passes through the glenoid cavity formed by the shoulder girdle and inserts on top of the humerus. contracts causes the counteraction which is the elevation of the wing during the upstroke

supracoracoideus

diapsid skulls

temporal openings are present in the skull

describe the first cervical vertebra of birds

the atlas contains a single condyle for attachment to the skull which allows for a greater range of head movement

Achilles tendon

the distal gastrocnemius tendon in humans attached to the heel.

What Many herptiles survive well on small amounts of food due to

the efficiency of ectothermy

sinoatrial(SA) node

the pacemakes of the heart, located in right wall of atrium

hamstring muscles

three muscles located on the caudal part of the thigh region. not only extend the hip joint but are also the main flexors of the stifle joint

triceps brachii muscle

three proximal head attachments and extends from teh distal scapula and proximal humerus down to the olecranon process of the ulna. Extends the elbow joint when it contracts

two bones located in midsection of avian leg

tibiotarsus, fibula

deltoid

tringular muscle extends from lateral portion of scapula down to the humerus. It is an abductor muscle and flexes the shoulder joint

quadrates

two small movable bones that the lower bill of birds beak hinges on

pectoral

two(one deep, one superficial) located on each side of the sternum. Both extend from sternum to the humerus and act as adductor muscles of the front leg

Multi-unit smooth muscle

type of smooth muscle composed of individual smooth muscle cells or small groups of cells. Found where small, delicate involuntary contractions are needed. Requires nerve impulse to stimulate contraction

describe the skull of anurans

typically broad and fenestrated, with fewer bones than those of other amphibians. the parts of the skull involved with olfaction and hearig are better developed, but eh palate is poorly developed and dentition is reduced

Brachium

upper arm. area of thoracic limb between the elbow and shoulder

perching reflex

when a bird bends its legs to perch, the tendons also bend and pull the toes closed around teh perch. this allows the bird to grip its perch firmly while sleeping

hibernation=brumation

when temperatures go out of the POTZ range, hibernation may occur. Herptiles that are hibernating do not feed and are minimally active until environmental temperatures return to POTZ

aerobic metabolism

when the oxygen supply is adequate to keep up with the energy needs of the fiber and the maximum amount of energy is extracted from each glucose molecule

glenoid cavity(triosseal canal)

wing attaches to the body by forming a joint in this cavity.

avian appendicular skeleton

wings, shoulder bones, legs, pelvic bones

how does viscera contract?

without the need for external stimulation. Reacts to stretching by contracting more strongly.

Adenosine diphosphate

"discharged" form of ATP. Nucleotide containing two phosphoric acid groups. When a phosphate group is split off of an ATP producing ADP, energy is released that powers the sliding of the actin and myosin filaments in muscle over each other. When it is reattached, ADP converts back to ATP and the molecule is ready to provide energy again

Why does an animal breathe heavily for awhile after heavy exercise?

To replace the amount of oxygen that is used to convert lactic acid to glucose in the liver

What ion, released from the sarcoplasmic reticulum by a nerve impulse, starts the contraction process in a muscle fiber?

calcium

which type of muscle is called involuntary striated muscle

cardiac

Which movement does contraction of the triceps brachii cause

extension of the elbow

Actin filament

formed of one of the two contractile proteins of muscle--slide over each other to produce muscle contraction. Two strands of protein twisted together to form a helical structure similar in appearance to a DNA molecule.

Myofibril

microscopic, fiberlike structures that occupy most of the cytoplasm in skeletal muscle cells. composed of thousands of protein filaments.

Creatine phosphate

molecule in muscle cells that splits to release the energy necessary to reattach the detached phosphate group to ADP to convert it back into ATP.

skeletal muscle

multinucleated, striated, voluntary muscle that enables conscious movement of an animal. moves the bones of the skeleton

Antagonist

muscle or muscle group that directly opposes the action of the agonist

Smooth muscle

nonstriated, involuntary muscle having only one nucleus per cell; the type of muscle found in soft iternal organs and structures.

Motor unit

one nerve fiber and all the skeletal muscle fibers it innervates---allows for large, powerful movements

Myosin filament

one of the two contractile proteins of muscle that slide over each other to produce the shortening of the muscle cell that we refer to as muscle contraction. Myosin moleculr has a twisted tail attached to two globular heads that form cross-bridges to actin and interact with the actin to shorten the sarcomere during muscle contraction.

Sarcoplasmic reticulum

organelle in a muscle cell that is equivalent to the endoplasmic reticulum of other cells. It is equivalent to the endoplasmic reticulum of other cells. It stores calcium ions necessary to initiate teh muscle contraction process. Release of CA+ from the sarcoplasmic reticulum is stimulated by a nerve impulse

Abductor muscle

outward movement--flexes the shoulder joint

what's the name of the basic contracting unit of a skeletal muscle

sarcomere

Twitch contraction

single skeletal muscle fiber contraction

which type of muscle is referred to as voluntary striated mucle

skeletal

Voluntary striated muscle

skeletal muscle

Nonstriated involuntary muscle

smooth muscle

Synergist

something that aids the action of something else. A synergistic muscle contracts at the same time as a prime mover and assists it in carrying out its action

Cardiac muscle

striated, involuntary muscle found exclusively in heart. Autonomic. One centrally located nucleus and intercalated discs that form connections between muscle branches.

Dense body

structures in smooth muscle cells to which the small contractile units of actin and myosin attach.

which structures connect muscles to bones

tendons

Neuromuscular junction

the "connection" between the end bulb of a motor nerve fiber and a skeletal muscle cell.

Diaphragm

the thin, dome-shaped sheet of muscle that forms the boundary between the thoracic and abdominal cavities.

Endomysium

thin, delicate layer of connective tissue that surrounds each individual skeletal muscle fiber.

Cross-bridge

tiny "levers" on the myosin filaments of muscle.

Epimysium

tough, connective tissue layer that covers and delineates individual muscles. Surrounds groups of skeletal muscle fascicles.

Tendon

tough, fibrous connective tissue bands that connect skeletal muscles to bones

Visceral smooth muscle

type of smooth muscle found in the walls of many soft internal organs, such as the intestine, urinary bladder, and uterus. Cells are linked to form large sheets that show rhythmic waves of contraction without external nerve stimulation

Lactic acid

waste product of anaerobic metabolism in skeletal muscle; an end mproduct of the metabolism of carbohydrates. It is created by the conversion of pyruvate into lactic acid after the fermentation of cellulose. Build up of lactic acid in a muscle that has been forced into anaerobic mode by overstrenuous activity can cause discomfort

Sarcomere

basic contracting unit of a skeletal muscle. consists of actin and myosin filaments between z lines in a uscle cell. myofibrils are composed of many sarcomeres stacked end to ehd

three phases of twitch contraction

1) latent phase-brief hesitation between stimulus and beginning of actual contraction(0.01sec) 2) contracting phase(0.1 sec) 3) relaxation phase(0.05sec)

Contributing factors to lightness of avian skeleton

1) reduction in number of bones 2) fusion of bones to form plates that provide strength and simplify movements 3) reduction in the density of bones 4) loss of internal bone matrix(bones are generally hollow and filled with air spaces)

how are muscles named

Action Shape Location Direction of fibers Number of heads or divisions attachment sites

Herptiles

Amphibians and Reptiles

extremely permeable nature of amphibian skin allows them to absorb the water they need from the environment.

Amphibians do not drink.

Four orders of class Reptilia

Crocodylia(alligators/crocs) Squamata(snakes/lizards) Chelonia(turtles/tortoises) Rhynocephalia(tuataras)

Muscle contraction AND Muscle relaxation require

Energy

three orders of class Amphibia

Gymnophiona(caecilians) Anura(frogs/toads) Caudata(salamanders/newts)

muscle contractions of cardiac cells

If two cells touch, the slower contracting cell will adapt to the faster cell's contraction rate contracts without any external stimulation contract in a rapid, wavelike fashion. impulse that coordinates the contraction spreads from cell to cell across the intercalated discs like a wave

myoglobin

Oxygen is stored attached to the large protein molecule called myoglobin

what is the function of intercalated discs

Transmit impulses from cell to cell securely fasten cells together

Why might it be of clinical importance to know the origin and insertion of a muscle?

By knowing the origin and insertion of a muscle, you can predict the action of the muscle without actually seeing the muscle contract.

If individual muscle fiber contractions obey the all-or-nothing principle, how does an animal control the size and strength of its muscular movement

By the number of fibers in a muscle that contract

What are the differences among a skeletal muscle fiber, a skeletal muscle myofibril, and a skeletal muscle protein filament?

A muscle fiber is one muscle cell. The muscle fiber is made up of many muscle myofibrils. Within the myofibrils are the protein filaments myosin and actin.

Describe the structure and function of tendons, aponeuroses, and ligaments

A tendon is a band of fibrous connective tissue that attaches muscle to bone. An aponeuroses is a broad sheet of fibrous connective tissue. Ligaments are bands of fibrous connective tissue present in and around many synovial joints.

What molecules in a muscle act as the "batteries" to power the sliding of the actin and myosin filaments? What molecules function as the "battery chargers"

Adenosine triphosphate (ATP) Creatine phosphate (CP)

What is myoglobin and why is it important

Myoglobin is a large protein in muscle that can store oxygen for times, like during strenuous exercise, when more oxygen is needed by the muscle.

Which contractile protein filaments make up the dark bands of skeletal muscle cells? Which make up the light bands?

Myosin myofilaments Actin filaments

Describe the effect of nerve stimulation on the functioning of visceral smooth muscle vs multi-unit smooth muscle

Nerve stimulation does not initiate smooth muscle action; it modifies it

What is the general effect of sympathetic nervous system stimulation on visceral smooth muscle? What is the effect of parasympathetic nervous system stimulation?

Parasympathetic nerve stimulation increases smooth muscle activity

List the components of neuromuscular junction and describe the function of each component.

Sites where the ends of motor nerve fibers connect to muscle fibers are called neuromuscular junctions. Nerve impulse coming down the motor nerve fiber to the synaptic releasing acetylcholine which diffuses across the synaptic space and binds to receptors on the sarcolemma. This starts the process of leading to muscle fiber contraction. Acetylcholinesterase in the synaptic space removed the acetylcholine molecule and splits is apart ending the nerve impulse.

What are the main differences in the structures and functions of skeletal muscle, cardiac muscle, and smooth muscle?

Skeletal muscle is composed of long, multinucleated cells that are under conscious control. They are striated when viewed microscopically. They move the bones that move the animal's body. Cardiac muscle is found only in the heart. It is made up of striated muscle cells that are not under conscious control. The cells have only one nucleus each. Intercalated discs join cardiac muscle cells end to end. Smooth muscle cells are nonstriated and have a single nucleus. They are not under conscious control. They are found in the walls of internal organs and locations, such as the eye, where delicate movements are necessary.

Involuntary muscle

Smooth muscle

Describe a smooth muscle cell in terms of its size, shape, number of nuclei, and appearance under the microscope

Smooth muscles are small and spindle shaped. They are not striated nor are they voluntary. They would be classified as involuntary, nonstriated muscles. They have one nucleus per cell.

What is the general effect of sympathetic nervous system stimulation on cardiac muscle? What is the effect of parasympathetic nervous system stimulation?

Sympathetic nerves cause the heart to beat harder and faster. Parasympathetic nerves cause the heart to beat slower and with less force.

Describe the effect of a cardiac muscle's nerve supply on its functioning.

The nerve supply to cardiac muscle does not initiate cardiac muscle cell contraction but it can modify the contraction

What is the origin of a muscle? The insertion?

The origin of a muscle is the most stable attachment site. The insertion of a muscle is the site that undergoes the most movement when a muscle contracts.

List the three types of muscle and describe the general characteristics of each type

The three types of muscle are skeletal, smooth, and cardiac. Skeletal muscle is controlled by the conscious mind and moves the bones of the skeleton. Smooth muscle carries out most of the unconscious, internal movements of the body. Cardiac muscle is found only in the heart and makes up the structure of the heart.

What are the main differences between visceral smooth muscle and multi-unit smooth muscle

Visceral smooth muscle is found in the walls of internal soft organs (viscera). The muscle cells are linked to form large sheets. Fine movement is not possible because the contractions are strong. Multiunit smooth muscles are small and delicate. They are made up of individual cells or small groups of cells. They are found where small, delicate contractions are needed.

Differentiate between visceral smooth muscle and multi-unit smooth muscle

Visceral smooth muscle is found in the walls of many internal soft organs. muscle cells are linked to form large sheets in the walls of organs such as intestines, uterus, bladder. Experiences large, rhythmic movements Multi-unit smooth muscle: small and delicate. made up of individual smooth muscle cells or groups of cells. found where small, delicate contractions are needed such as iris, walls of blood vessels

Muscle

a collection of tissues that support the body and enable it to move, thermoregulate, and transport materials.

Fascicle

a group of skeletal muscle fibers bound together by a layer of fibrous connective tissue called the perimysium.

Fixator

a muscle that stabilizes a joint so that other muscles can produce effective movements of other joints

Inspiratory muscle

a muscle whose action is to increase the size of the thoracic cavity; this causes air to be drawn into the lungs, thereby producing inspiration(inhalation)

Myoglobin

a protein in muscle cells that has properties similar to hemoglobin. Can store and release large quantities of oxygen to fuel aerobic metabolic processes in muscle cells.

Z line(Z disc)

dark line in teh center of the light band(I band) of skeletal muscle. Z lines are discs to which the actin filaments are attached.

which muscle antagonizes the pectoral muscle

deltoid

what contracts during inspiration

diaphragm

What is a sarcomere and what are its components?

each contractile unit of a myofibril--the basic contracting unit of skeletal muscles.

Intercalated disc

end-to-end attachment sites between adjacent cardiac muscle cells. Fasten the cells together and transmit impulses from cell to cell. This allows group of muscle cells to function as a single unit

List and describe the roles of connective tissues in skeletal muscles

endomysium: delicate connective tissue layer surrounds each individual skeletal muscle fiber. perimysium: tougher connective tissue composed of reticular fibers and thick collagen fibers that binds fasicles(Bundle of fibers) together. epimysium: fibrous connective tissue layer composed largely of tough collagen fibers. the outer covering of the entire muscle.

List the locations and actions of muscles of respiration

inspiratory muscles: increase the size of the thoracic cavity expiratory muscles: decrease thoracic cavity diaphragm-main inspiratory muscle external intercostal muscles affect inspiration by contraction which rotates the ribs upwards and forward increasing the size of the thoracic cavity and drawing air inward internal intercostal muscles: expiratory--rotate the ribs backward which decreases the size of the thorax and pushes air out

H band

light colored area located in the middle of the A band. Made up of myosin filaments only with no overlapping actin filaments. Does not cover the entire width of the myosin filament.