HESI ANATOMY & PHYSIOLOGY MUSCULAR SYSTEM

Question 1

Muscles

Answer 1

move bones by contracting and relaxing

heart is largely composed of muscles and the blood vessels contain a layer of muscles.

Question 2

3 types of muscle tissue

Answer 2

skeletal, cardiac, and smooth muscle

Question 3

Skeletal muscle

Answer 3

moves bones and generates heat.

cells in skeletal muscle are called myocytes and they contain a reddish pigment called myoglobin

Question 4

Straiations

Answer 4

striations mark the contractile units called sarcomeres.

Question 5

Cardiac muscle

Answer 5

it is also striated.

cells are called cardiomyoctyes which have 1 nucleus.

contains special cell junctions called intercalated discs which help the cells contract together which is important in moving blood through the heart.

contract on its own because it contains areas of special tissue called nodes

Question 6

Smooth muscle

Answer 6

less organized structure than skeletal or cardiac muscle.

cells with only 1 nucleus and there are no striations

found in the digestive, reproductive, and urinary systems and in blood vessels.

involuntary control and can sustain contractions for long period of time

produce a wave like contraction called peristalsis - food moves through the digestive tract by way of peristalsis.

Question 7

Skeletal muscle

Answer 7

arranged in bundles within bundles

most outer layer contains connective tissue called fascia

Question 8

epimysium

Answer 8

Deep to the fascia we see a layer of dense connective tissue

Question 9

fascicles.

Answer 9

contains an outer layer called the perimysium and inside each fascicle there are bundles of muscle fibers.

Question 10

Describe the locations of skeletal muscles,

Answer 10

origin and insertion.

Question 11

Origin of a muscle

Answer 11

less mobile end of a joint.

Question 12

Insertion Muscle

Answer 12

more mobile end of a joint.

Question 13

tendons.

Answer 13

Muscles connect to bones through dense connective tissue

broad and flattened.

Question 14

Muscles of the neck

Answer 14

sternocleidomastoid - which is an important muscle for turning the head, and the trapezius which helps to shrug the shoulde

levator scapulae - elevates the scapula.

scalenes - deep muscles of the neck that assist in laeral flexion.

Question 15

Muscles of the Arm

Answer 15

supraspinatus muscle - rotator cuff muscles and is the muscle most frequently injured in rotator cuff injuries.

below the supraspinatus - infraspinatus and teres minor muscles, both are rotator cuff muscles

One the **back of the arm we see the triceps brachii **which is a 3 headed muscles. The triceps allows you to straighten your elbow.

Muscles on the front of the arm include the biceps brachii and brachialis. Both allow you to flex your elbow

Question 16

Muscles in the forearm

Answer 16

front of the forearm can be called flexors

back of the forearm can be called extensors.

muscles that allow for rotation - pronator teres and anaconeus.

Question 17

Muscles of the hand

Answer 17

pollicis - thumb

brevis - short

Question 18

Muscles of the Leg

Answer 18

Muscles on the front or anterior side of the leg include the sartorius or Tailor’s muscle

quadriceps muscles - rectus femoris, vastus medialis, and vastus lateralis

4th quad - beneath the rectus femoris and is called the vastus intermedius.

psoas major muscle - ombines with the iliacus to form the iliopsoas which is an important muscle in hip flexion

Question 19

adductor group

Answer 19

muscles and gracilis that work to pull the leg inward (adduction)

Question 20

gluteal muscles

Answer 20

located in the posterior hip region.

deepest gluteus muscle - gluteus mininus.

gluteus medius - pelvic stability and a site for injections.

gluteus maximus - gluteus medius muscle which is an important muscle in pelvic stability

Question 21

hamstrings

Answer 21

3 hamstring muscles

lateral to medial we see the biceps femoris, semimembranosus and semitendinsosus

Question 22

(Front) anterior lower leg

Answer 22

tibialis anterior, extensor digitorum and a group of muscles called the fibularis muscles

Question 23

(Back) posterior of the lower leg

Answer 23

gastrocnemius (calf muscle)

soleus and the achilles or calcaneal tendon

small muscle here called the plantaris muscle as well that is absent in 8-12% of the population

Question 24

Foot muscles

Answer 24

abductor hallucis - moves the big toe into abductio

flexor digitorum brevis - short muscle that flexes the toes.

Question 25

neurotransmitters

Answer 25

bring the message from the nerve to the muscle

Other chemical messengers that tell the protein filaments to contract then pass on the message

Question 26

energy comes from ATP.

Answer 26

ATP connects to one type of filament and extracts the energy so that it can pull the other filament along.

Question 27

motor neuron

Answer 27

connects to a skeletal muscle at a special area called the motor end plate.

Question 28

Process of Motor Neuron

Answer 28

1) in the motor neuron will cause the influx of calcium into the axon terminal
2) which promotes the release of the neurotransmitter acetylcholine from the axon terminal
3) Acetylcholine moves across the synaptic cleft to the motor end plate
4) romotes the opening of sodium channels causing sodium to rush into the skeletal muscle cell
5) keletal muscle is polarized and the movement of sodium causes it to depolarize.
6) effect on the sarcoplasmic reticulum

Question 29

T-tubules.

Answer 29

reach into the muscle fiber and encircle the sarcomere

connects to the outside of the cell it is filled with extracellular fluid

Question 30

sarcoplasmic reticulum

Answer 30

network of membranous channels called cisternae

transports calcium so it contains a high concentration of calcium

responds to the depolarization of the muscle cell by opening calcium channels in the terminal cisternae of the sarcoplasmic reticulum

Question 31

Cisternae

Answer 31

T-tubules are wider and called terminal cisternae.

A tubule and the two adjacent terminal cisternae are called a triad.

Question 32

Summary of sacriplasmic reticulm

Answer 32

To summarize, the sarcoplasmic reticulum is a network of tubules that wraps around the muscle cell. Think of a loosely knit winter sweater.

The sarcoplasmic reticulum will take calcium from the blood and store it until the muscle cell depolarizes. Once it does, the sarcoplasmic reticulum releases calcium into the muscle cell.

Question 33

Actin

Answer 33

double helix protein and myosin has large globular protein heads.

Thin filament

Question 34

Myosin

Answer 34

the thick filament.

large globular protein heads.

Question 35

troponin-tropomyosin complex.

Answer 35

double helix protein complex wrapped around actin

Question 36

m line

Answer 36

middle of this structure there is only myosin

Question 37

z lines

Answer 37

called a sarcomere.