Physiology recap

Question 1

What are osteoclasts?

Answer 1

bone forming cells (oesteiod that mineralises into bone)

Question 2

What are osteocytes and what do they do

Answer 2

mature bone cells

Question 3

What do osteoclasts do

Answer 3

break down and remodel bone

constant turnover (5-7% a week)

Question 4

What do osteocytes do?

Answer 4

maintain calcium homeostasis

Question 5

where are osteoclasts found

Answer 5

on the surface of the bone

Question 6

what are the 2 types of bone

Answer 6

compact ( cortical - outside of bone)

spongy (trabecular - middle of bone)

Question 7

What is the orientation of muscle filament s

Answer 7

6 thin actin filaments surrounding 1 thick myosin filament

Question 8

What are 4 ways to classify muscle fibre types

Answer 8

Histochemical

Biochemical

Morphological

Physologic

Question 9

3 types of muscle fibre

Answer 9

type 1

type 2a

type 2x

Question 10

what are muscle spindles?

Answer 10

stretch sensors

Question 11

what happens when the muscle is stretched?

Answer 11

spindles are stretched sending a impulse to spinal coord causing motor neurones to fire contracting the muscle to prevent tearing

Question 11

What are Golgi tendon organs

Answer 11

tension sensors

Question 12

What happens when a large load is applied to a muscle (tendon)

Answer 12

discharge of the GTO and the muscle relaxes

Question 13

what does having sarcomeres in series improve?

Answer 13

velocity of contraction

Question 14

what does having sarcomeres in parallel improve?

Answer 14

force of contraction

Question 16

5 shapes of parallel pennation angle

Answer 16

Flat 
Fusiform (flat with a middle bulge)
Strap
Convergent (triangular - pec)
Circular (eg around eyes)

Question 17

Where is the sarcomere located?

Answer 17

Between the 2 Z-lines

Question 18

What are the thick filaments?

Answer 18

Myosin

Question 19

What are the thin filaments?

Answer 19

Actin (G actin binding sites covered by tropomyosin)

Question 20

What is titin and does it do?

Answer 20

An elastic filament - connects myosin to Z discs - prevents over stretching and allows for muscle recoil

Question 21

What does the I band contain?

Answer 21

Only actin filaments

Question 22

What does the A band contain?

Answer 22

Both action and myosin filaments (overlapping)

Question 23

What does the H zone contain?

Answer 23

Only myosin filaments

Question 24

Sliding filament theory overview Stage 1

Answer 24

Nerve impulse -> ACh -> Ca+ release from sarcoplasmic reticulum -> tropomyosin moves exposing actin binding sites

Question 25

Sliding filament theory overview Stage 2

Answer 25

Cocked myosin head binds to active site on actin -> Pi is released forming strong cross bridge bond

Question 26

Sliding filament theory overview Stage 3

Answer 26

ADP released from myosin head = power stroke

new ATP binds releasing the bond allowing the process to repeat

Question 27

3 types of tendon attachment

Answer 27

Unipennate - muscle fascicles only on side of tendon

Bipennate - both sides

Multipennate - many directions of attachment

Question 28

Length - tension relationship
(active tension)

which length has best force generating capacity

Answer 28

Resting because there is the most overlap

too short - too much overlap already

too long - not enough overlap to generate force

Question 29

How do passive tension producing elements effect the length - tension relationship?

Answer 29

the elastic components of the muscle can generate more force when stretched (muscle lengthened)

Question 30

How is total tension calculated?

Answer 30

Active tension + passive tension = Total tension

Question 31

Force velocity curve relationship explained when shortening (concentric)

Answer 31

Peak force is produced when there is 0 velocity (most cross bridges formed at this point)

^ velocity = decrease power

Question 32

Force velocity curve relationship explained when lengthening (eccentric)

Answer 32

As velocity increases force production increases as a load higher than isometric is applied forcing the eccentric contraction (lowering phase of bench)