Muscles

Question 1

How do horses generate movement?

Answer 1

-muscles contract and pull on a tendon
-the tendon is attached to a bone
-the muscle-tendon unit causes the bones to move

Question 2

Adduction

Answer 2

moving in towards the body

Question 3

Abduction

Answer 3

moving out away from the body

Question 4

Flexion

Answer 4

closing the angle of the joint

Question 5

Extension

Answer 5

opening the angle of the joint

Question 6

How are muscles and tendons named?

Answer 6

for their type of movement, their location, and/or the structures they move

Question 7

Extensor carpi radialis

Answer 7

extends the knee (carpus), located along the radius (on the dorsal side)

Question 8

Flexor carpi radialis

Answer 8

flexes the knee, located along the radius (on the palmar side)

Question 9

A muscle is a…

Answer 9

bundle of fasicles

Question 10

A fasicle is a…

Answer 10

bundle of muscle fibers

Question 11

Muscle fibers are…

Answer 11

bundles of myofibrils

Question 12

Where does muscle contraction occur?

Answer 12

in the sarcomere

Question 13

What is the thick filament made of?

Answer 13

myosin

Question 14

What is the thin filament made of?

Answer 14

actin

Question 15

What is the sarcomere made up of?

Answer 15

the thick and thin filaments

Question 16

The thin filament is anchored to…

Answer 16

the Z line

Question 17

The thick filament is anchored to…

Answer 17

the M line

Question 18

When the muscle relaxes what is occuring?

Answer 18

tropomyosin is blocking the binding sites on Actin

Question 19

When the muscle is contracting what is occuring?

Answer 19

tropanin releases tropomyosin so myosin can bind to actin and the muscle can contract

Question 20

Steps to muscle contraction:

Answer 20

-a neural impulse occurs, signaling a need to contract
-the neural signal causes a chain of reactions resulting in the release of calcium within the muscle cell
-the calcium causes a change that allows the thin and thick filaments of the sarcomere to interact
-ATP is used as the thick and thin filaments associate and disassociate-causing the sarcomere to shorten (contraction)

Question 21

How many phosphates are in ATP

Answer 21

3

Question 22

How many phosphates are in ADP

Answer 22

2

Question 23

Where do muscles get ATP

Answer 23

-stored ATP
-creatine phosphate
-aerobic (oxidative) metabolism
-anaerobic (glycolytic) metabolism

Question 24

What is stored ATP good for?

Answer 24

brief activities, very limited amounts

Question 25

What is creatine phosphate good for?

Answer 25

short activities, very limited amounts

Question 26

Aerobic (oxidative) metabolism

Answer 26

-uses carbohydrates or fat -efficient -sustainable -not always fast and needs oxygen

Question 27

Primary sources of fuel for aerobic ATP production:

Answer 27

-fat -carbohydrates

Question 28

What is not a primary energy source for contracting muscle?

Answer 28

protein

Question 29

Which is the more efficient fuel source for aerobic ATP production?

Answer 29

fat

Question 30

Fat is...

Answer 30

-the most efficient source -the most abundant source

Question 31

Where is fat stored?

Answer 31

-some in muscle cells -some in adipose tissue

Question 32

What are fats stored as?

Answer 32

triglycerides

Question 33

What is broken down in fats to produce ATP?

Answer 33

fatty acids

Question 34

The process of aerobic ATP production with fat is relatively...

Answer 34

slow

Question 35

What is the storage form of carbohydrates in the body?

Answer 35

gycogen

Question 36

Where is glycogen stored?

Answer 36

-in the muscle cells -in the liver

Question 37

What is glycogen broken down to?

Answer 37

glucose

Question 38

Glycogen stores are ______ ______ compared to fat stores

Answer 38

very small

Question 39

Blood glucose fuel source for aerobic ATP production

Answer 39

muscle cells can take up glucose from the bloodstream for ATP

Question 40

Sources of blood glucose

Answer 40

-food (primarily starches and sugars) -liver glycogen -gluconeogenesis in the liver

Question 41

Anerobic (glycolytic) metabolism can only use _______ in ATP production

Answer 41

carbohydrates

Question 42

Anaerobic (glycolytic) metabolism:

Answer 42

-not as efficient -fast -oxygen not needed (muscles don't need to be warmed up yet) -accumulation of H+ can lead to fatigue

Question 43

Anaerobic (glycolytic) metabolism produces what with ATP from glucose?

Answer 43

lactic acid

Question 44

What determines which energy system is used?

Answer 44

-oxygen availability -activity -fiber type -training

Question 45

Draft horses pulling heavy loads would use which ATP production system?

Answer 45

stored ATP and creatine-P

Question 46

Endurance horses would use which ATP production system?

Answer 46

most aerobic metabolism

Question 47

Racehorses would use which ATP production system?

Answer 47

aerobic and anaerobic metabolism (anaerobic allows the extra speed past what aerobic provides)

Question 48

Muscle fiber types:

Answer 48

Type I, Type IIA, and Type IIX

Question 49

Postural muscles are more of which fiber type?

Answer 49

more type I (don't have to contract fast)

Question 50

Driving muscles are more of which fiber type?

Answer 50

more type II (more exercise associated)

Question 51

Fiber type distribution in breeds

Answer 51

it involves some genetics: -arabians have more type I and type IIA -quarter horses have more type IIA and type IIX

Question 52

Type I muscle fibers

Answer 52

Fatigue resistant because: -slow contraction ("slow-twitch") -red fibers (high in myoglobin) -narrow diameter (better nutrients in/out) -high blood flow -many mitochondria (where a lot of ATP is produced) -relatively high in fat (very aerobic, can utilize the fat) -relatively low in glycogen

Question 53

Type IIA muscle fibers

Answer 53

Moderately fatigue resistant because: -fast contraction speed ("fast-twitch") -red fibers (moderate in myoglobin) -medium diameter -good blood flow -moderate mitochondria -medium in fat -medium in glycogen -function mostly aerobic -can produce ATP anaerobically

Question 54

Type IIX muscle fibers

Answer 54

NOT fatigue resistant because: -fast contraction speed ("fast-twitch") -white fibers (low in myoglobin) -largest in diameter (nutrients harder to get in/out) -less blood flow -fewer mitochondria -low in fat -high in glycogen -mostly anaerobic -have high buffering capacity (better able to deal with lactic acid)

Question 55

What muscle fiber is mostly recruited for low intensity exercise?

Answer 55

type I

Question 56

What muscle fiber is mostly recruited for high intensity exercise?

Answer 56

type IIX

Question 57

Muscle fiber type recruitment:

Answer 57

1.) type I - will still be used as exercise intensity increases 2.) type IIA - continues to be recruited 3.) type IIX - all the muscle fibers are recruited now

Question 58

Effects of training on the respiratory system

Answer 58

minimal effects

Question 59

Effects of training on the cardiovascular system

Answer 59

-max HR is not changed -stroke volume may increase -increased capillary density in muscles (increases blood flow-increases O2)

Question 60

With training, VO2 max _______

Answer 60

increases -horses can exercise for a longer period of time

Question 61

With training, horses use _______ more efficiently

Answer 61

O2 -do the same work but use less oxygen

Question 62

Effects of training on muscle:

Answer 62

-increase in aerobic metabolism (use more fat and spare carbs, produce less lactic acid) -increase in muscle glycogen concentrations (more substrate available for ATP synthesis) -increase in intracellular buffering (can tolerate more lactic acid production)

Question 63

With training less _______ is produced at any given intensity

Answer 63

lactate

Question 64

With training horses use less _______ because...

Answer 64

glycogen because they'll be using more fat