A&P Lab Quiz 11, 12, 13

List 3 reasons why the connective tissue sheaths of skeletal muscle are important

1. Supporting and binding the muscle fibers 2. providing strength to the muscle as a whole 3. Provide a route for the entry and exit of nerve blood vessels that serve the muscle fibers

Why are there more indirect- that is, tendinous- muscle attachments to bone than there are direct attachments?

Because they can span rough bony prominences that would destroy the more delicate muscle tissues and because relatively small size, more tendons than muscles can pass over joints.

How is an aponeurosis functionally similar to a tendon?

Both serve to attach muscles to bone or to other muscles

which joint, the hip or knee is more stable

hip

ball and socket joint

hip joint a multiaxial joint

cartilaginous joints

includes joints between the vertebral bodies and the pubic symphysis Found in the epiphyseal plate

Synovial joints

includes shoulder, elbow, and wrist joints are all freely movable or diathrotic

Hinge

interphalangeal joints joint between jaw and skull uniaxial joints

plane

intervertebral joints (between articular processes) joint between talus and tibia/fibula

pivot

joint between the axis and atlas joint between forearm bones and wrist uniaxial joints

Sarcolemma

plasma membrane of a muscle fiber

Epimysium

superficial sheath that covers the entire muscle

Fibrous

sutures are the most remembered examples Found in gomphosis

Which structure in the synovial joint produces synovial fluid?

synovial membrane

Agonist

term for the biceps brachii during forearm flexion

Fixator

term for the rotator cuff muscles and deltoid when the forearm is flexed and the hand grabs a tabletop to lift the table

antagonist

term for the triceps brachii during forearm flexion

synergist

term that describes the relation of brachioradialis to biceps during forearm flexion

Endomysium

thin areolar connective tissue surrounding each muscle fiber

The glenoid labrum can become torn from overuse or direct injury to the shoulder joint. Considering the function of the glenoid labrum, describe some of the consequences of a large tear in the glenoid labrum.

A decreased range of motion, may cause shoulder dislocation and a decrease in strength.

How does a tendon sheath differ from a bursa?

A tendon sheath is an elongated bursa/sac that around tendons while a bursa is a flattened fibrous sac wedged between adjacent structures.

myofilament

Actin or myosin containing structure

The bacteria Clostridium botulinum secretes botulinum toxin, a neurotoxin. The blocks the release of acetylcholine from the axon terminal of a motor neuron. Explain how the toxin binding would change the normal sequence of events at the neuromuscular junction.

Botulinum toxin binds to the motor neuron and prevents the acetylocholine from being released into the synaptic cleft. This prevents the initiation of an end-plate potential because there is no neurotransmitter to bind to the ion-channel receptor on the muscle cell motor end plate.

Sacromere

Contractile unit of muscle

Repetitive extension of the hand at the wrist and abduction of the hand can lead to lateral epicondylitis. Although sometimes called 'tennis elbow,' it more often affects individuals who dont play tennis. Based on the name lateral epicondylitis and the action described above, which muscle would most likely have microscopic tears in the tendon?

Extensor carpi radialis brevis

Necrotizing fasciitis is a serious bacterial infection. Necrosis is death of tissues in the body. Considering the organization of the connective tissue sheaths of skeletal muscle, explain how this infection could spread rapidly throughout the body.

It spreads quickly because the connective sheaths, particularly the epimysium, are all continuous with each other and with the superficial fascia, so there are no physical barriers.

Saddle

Joints between proximal phalanges and metacarpal bones uniaxial joints

Bruxism is a condition in which individuals, clench and/or grind their teeth. It often occurs as they sleep, leading to jaw pain and damaged teeth. Which muscles contract during this nocturnal event?

Masseter and temporalis

name 2 important factors that contribute to stability of the knee

Menisci and intracapsular cruciate ligament

The menisci in the knee joint can be torn for a variety of reasons. Considering the structure of the menisci, would you expect these tears to heal on their own? Why or why not?

Possibly, if it occurs in the red zone, the menisci heals on its own, but if its in the white zone its doesnt because there is no blood supply so it cant heal on its own.

How does an aponeurosis differ from a tendon structurally?

Tendons are strong and cord-like and attach muscle to bone; aponeurosis are sheet-like and attach muscle to muscle

A physician diagnoses you with 'olecranon bursitis'. Predict the location and cause of the swelling that you are experiencing.

The location is in the elbow and the cause is due to water or fluid in the elbow becoming inflammed.

Myofibrils

a long organelle with a banded appearance found within muscle fibers

Condyle

biaxial joints

Fascicle

bundle of muscle fibers

Perimysium

connective tissue covering a bundle of muscle fibers

Tendon

cord of collagen fibers that attaches a muscle to a bone

name 2 important factors that contribute to stability of hip joint

deep socket and strong reinforcing ligament