PHYSIO BLOCK 2

Question 1

Muscle funtions

Answer 1

1. Locomotion
2. Respiration
3. Digestion
4. Parturition
5. blood and lymph circulation
6. Swallowing
7. Generation of body heat

Question 2

Muscle properties

Answer 2

1. Contractility
2. Excitability- receive and respond to stimulus
3. Extensibility- to stretch
4. Elasticity- to return to original shape

Question 3

Types of muscles

Answer 3

1. Smooth- contracts slow, involuntary, not striated
2. Skeletal- contracts rapid, voluntary, striated
3. Cardiac- contracts rapid, involuntary, striated

Question 4

Where is smooth muscle found?

Answer 4

viscera, blood vessels

Question 5

Where is skeletal muscle found?

Answer 5

Trunk, extremities, head and neck

Question 6

Skeletal muscle

Answer 6

• contracts rapid, voluntary, striated
• attached to bone by tendon
• contraction causes body movement
• stimulated by motor nerve

Question 7

Levels of organization in skeletal muscle

Answer 7

• Epimysium
• Fascicle
• Perimysium
  -Endomysium
  -Sarcolema
• Muscle fibers

Question 8

Epimysium

Answer 8

Sheath of connective tissue, surrounds muscle

Question 9

Fascicle

Answer 9

Cluster of muscle fibers (cells) inside muscle

Question 10

Perimysium

Answer 10

Connective tissue from epimysium that wraps around each fascicle

Question 11

Endomysium

Answer 11

Connective tissue surrounds each muscle fiber, attached to sarcolema

Question 12

Sarcolema

Answer 12

thin cell membrane enclosing a skeletal muscle fiber (cell)

fuses with tendon fibers to form muscle tendons to connect muscle to bone

Question 13

Muscle fibers

Answer 13

alongated shape

contains contractile units

the pull is transmitted by endomysium, perimysium, and epimysium to tendon or aponeurosis to bone

Question 14

Types of muscle fibers

Answer 14

Type 1- red fibers

Type 2- white fibers

Question 15

Type 1 muscle fiber

Answer 15

• red fiber (for long distance running)
• slow contracting (SLOW TWITCH)
• rich in mitochondria
• oxidative mechanism

Ex: muscles to maintain posture… contracting all the time

Question 16

Type 2 muscle fiber

Answer 16

FAST TWITCH (fast contracting)

• easily fatigued
• few mitochondria
• glycolytic metabolism

Can be Type 2A- mixed oxidative- glycolytic or Type 2B- fast contracting, fast fatiguing glycolytic fibers

Question 17

Type 2A fibers

Answer 17

A type of fast twitch fiber

-mixed oxidative-glycolytic
- intermediate between type 1 and 2B

Ex: dogs muscles

Question 18

Type 2B fibers

Answer 18

type of fast twitch fiber

-fast contracting, easily fatigued
-depends on glycogen for energy

Ex: muscles for sprinting

Question 19

Myofibrils

Answer 19

Thousands of myofibrils are in each muscle fiber

made of linear repeating sarcomeres

Question 20

Sarcomeres

Answer 20

• contracts striated muscle fibers
• found between Z lines
• Contains myofilaments

Question 21

Myofilaments

Answer 21

found in sarcomere

• thin filament= actin, troponin, tropomyosin

Thick filament= myosin

Question 22

Myosin

Answer 22

thick myofilament that has a tail of helices and 2 heads that bind to ATP and ACTIN

Uses ATP for energy to contract

Forms cross bridges with actin

Question 23

Thin myofilaments

Answer 23

• Actin, troponin, tropomyosin

-2 helical strands of actin
-2 strands of tropomyosin

Question 24

Troponin

Answer 24

A thin myofilament, globular protein

Has affinity for Calcium ions

Question 25

Titin filamentous molecules

Answer 25

- Keeps myosin and actin in place - elastic molecule -Attaches myosin to Z disc

Question 26

Gs

Answer 26

A G protein that activates adenylyl cyclase and activates Ca+ channels to form cAMP

Question 27

G(i)

Answer 27

Inhibits adenylyl cyclase, activates K+ channels