Musculoskeletal System Physiology

Question 1

What are the four main characteristics of muscle tissue?

Answer 1

1. Excitability
2. Contractibility
3. Extensibility
4. Elasticity

Question 2

What characteristic is seen in all muscle types?

Answer 2

Excitability

Question 3

Definition of excitability?

Answer 3

Ability to receive and respond to stimuli

Question 3

Definition of contractibility?

Answer 3

Ability to shorten forcibly when stimulated

Question 4

Definition of extensibility?

Answer 4

Ability to be stretched

Question 5

Definition of elasticity?

Answer 5

Ability to recoil to resting strength

Question 6

What are the general functions of muscle tissue?

Answer 6

Movement
Maintain posture and body position
Stabilize joints
Generate heat
Support/protect organs

Question 7

What are the three main types of muscle?

Answer 7

Skeletal, cardiac, smooth

Question 8

Function of skeletal?

Answer 8

Movement/posture

Question 8

Function of cardiac?

Answer 8

Encompasses heart

Question 9

Function of smooth?

Answer 9

Present through many systems including urinary, vascular, respiratory

Question 10

What is the appearance of skeletal muscle?

Question 11

What is the appearance of cardiac muscle?

Question 12

What is the appearance of smooth muscle?

Question 13

List whether cardiac, skeletal, and smooth are involuntary or voluntary.

Answer 13

Cardiac- involuntary
Smooth- involuntary
Skeletal- voluntary

Question 14

List the functions of cardiac, skeletal, and smooth muscle.

Answer 14

Cardiac- blood circulation
Smooth- propels substances along internal pathways
Skeletal- locomotion

Question 15

List the location of skeletal, cardiac, and smooth muscles.

Answer 15

Skeletal- bones
Smooth- walls of hollow organs
Cardiac- walls of heart

Question 16

What is the function of the sarcolemma?

Answer 16

action potential conduction

Question 17

Function of transverse (T) tubule?

Answer 17

increases muscle fiber surface area

Question 18

What is the function of sarcoplasmic reticulum?

Answer 18

Stores Ca and releases on demand

Question 19

Discuss the excitation-contraction coupling process.

Answer 19

AP to sliding of myofilaments
Events that transmit AP along sarcolemma (excitation) are coupled to sliding myofilaments (contraction)

Ultimately Ca 2+ released and muscle contracts

Question 19

Function of ATP?

Answer 19

prepares myosin by binding with actin and moving it to a higher energy state

Question 19

What type of substance is troponin?

Answer 19

major protein

Question 19

Function of actin?

Answer 19

myosin binding site, holds tropomyosin and troponin

Question 20

Function of myosin?

Answer 20

Linking filaments, acts as a motor force

Question 21

Function of calmodulin?

Answer 21

Ca 2+ binding site

Question 21

Two functions of tropomyosin?

Answer 21

Stiffen and stabilize the actin core AND block myosin binding sites (in the relaxed state)

Question 22

Discuss the cross bridge cycle.

Answer 22

Ca 2+ binds to troponin and removes blocking action of tropomyosin Troponin changes shape Myosin binding sites are exposed Myosin and actin creates bridges and cycling begins

Question 23

Discuss the sliding filament theory.

Answer 23

Muscle fiber contracts when myosin filaments pull actin filaments closer together and shorten sarcomeres Once all sarcomeres shorten, contraction occurs