MCAT BIology Muscles and

Question 1

___ refers to reducing the angle of the joint

Answer 1

Flexing

Question 2

___ refers to increasing the angle of the joint

Answer 2

Extending

Question 3

___ fers to moving away from the body’s modiline

Answer 3

Abducting

Question 4

____ refers to moving toward the body midline

Answer 4

Adducting

Question 5

The point on the boner where a muscle attaches it called the __

Answer 5

origin of that muscle

Question 6

The point where the muscle attaches on the bone more distant from the center of the body is referred to as the muscle’s __

Answer 6

insertion

Question 7

___ filaments are attached to Z lines but not __ filaments

Answer 7

Thin filaments (actin) are attached to Z lies, but thick filaments are not

Question 8

The region of a myofibril with only thick filaments only seen in resting sarcomeres is referred to as__

Answer 8

H zone

Question 9

During muscle contraction, do the thin and thick filaments shorten?

Answer 9

No, the thin and thick filaments slide across each other to shorten the sarcomere without themselves changing in length

Question 10

Binding of ____ is necessary for the release of actin by the myosin head

Answer 10

a new ATP molecule

Question 11

Contraction of a muslce only occurs when ___ increases

Answer 11

cytoplasmic (Ca2+) increases

Question 12

What protein is responsible for ATP hydrolysis during muscle contraction?

Answer 12

Myosin is the protein with the ATPase activity

Question 13

The ___ is the synapse between an axon terminus (synaptic knob) and a myofiber

Answer 13

Neuromuscular junction (NMJ)

Question 14

The postsynaptic membrane ( the myofiber cell membrane) is known as the __

Answer 14

motor end plate

Question 15

What are the two ways that the nervous system can increase the force of contraction?

Answer 15

1. Motor unit recruitment

2. Frequency summation

Question 16

The liver picks up lactic acid in the bloodstream from the muscles and turns it into ___

Answer 16

pyruvate

Question 17

What is the cause of rigor mortis?

Answer 17

Results from complete ATP exhaustion, without ATP, myosin heads cannot release actin, and the muscle can neither contract nor relax

Question 18

These are the fibers that allow marathoners and long distance cyclists to run or bike for hours at a time

Answer 18

Type 1 slow twitch fibers

Question 19

Type ___ fast twitch fibers have more mitochondria than ___ and are thus more fatigue resistant

Answer 19

Type 2A fast twitch fibers have more than Type 2B

Question 20

___ are the fibers needs for explosive force like pole vault and dunking

Answer 20

Type 2B

Question 21

The function of T tubules in both cardiac and skeletal muscle is to

Answer 21

transmit APs into the interior of the large, thick cell

Question 22

___ is a functional syncytium not a structural synctium

Answer 22

Cardiac muscle cells ,because they are uninucleated but they are interconnected and allow AP’s to propagate through them

Question 23

In cardiac muscle cells some of the required calcium comes from __

Answer 23

extracellular environments through the voltage-gated calcium channels

Question 24

The voltage-gated calcium channels cause the cardiac AP to have a distinctive plateau, what are the two significant things of this plateau phase?

Answer 24

1. longer duration of contraction facilitates ventriular emptying (better ejection fraction)
2. Longer refractory period prevents disorganized transmission of impulses through the heart, and makes summation and tetanus impossible

Question 25

Smooth muscle does not have __ because the cells are much smaller and narrower than skeletal muscle cells and cardiac muscle cells

Answer 25

T-tubules

Question 26

Both smooth muscle and cardiac muscle are __

Answer 26

functional syncytium

Question 27

Thick and thin filaments are not organized in sarcomeres in smooth muscle, they are __

Answer 27

dispersed in the cytoplasm, thats why they are smooth

Question 28

The __ is not present in smooth muscle, smooth muscle contraction is regulated by calmodulin and myosin light-chain kinase (MLCK)

Answer 28

troponin-tropomyosin

Question 29

The __ and ___ regulate smooth muscle contraction

Answer 29

Calmodulin, and myosin light-chain kinase

Question 30

The axial skeleton consists of ___,___, and the__

Answer 30

skull, vertebral column, and the rib cage

Question 31

All bones other than skull, vertebral column, and rib cage are part of the ___

Answer 31

appendicular skeleton

Question 32

The main ingredients in ground substance of connective tissue is __

Answer 32

proteoglycans

Question 33

___ bones are the location of hematopoiesis

Answer 33

Flat bones such as the scapula, ribs, and bones of the skull

Question 34

Shaft of a long bone is the ___

Answer 34

diaphysis

Question 35

The flared end of long bones are __

Answer 35

epiphysis

Question 36

The diaphysis of long bones is a tube composed only of ___

Answer 36

compact bone

Question 37

Bone is composed of two principal ingredients ___ and ___

Answer 37

collagen and hydroxyapetite

Question 38

The basic unit of compact bone structure is the ___

Answer 38

osteon (referred to as Haversian system)

Question 39

joints are lined by hyaline cartilage known as __

Answer 39

articular cartilage

Question 40

___ connect bones to other bones

Answer 40

Ligaments

Question 41

___ connect bones to muscles

Answer 41

Tendons

Question 42

Immovable joints are called

Answer 42

Synarthroses

Question 43

Slightly movable joints are called__

Answer 43

amphiarthroses

Question 44

Freely movable joints are called

Answer 44

Diarthroses

Question 45

Most bone growth occurs by ___ in which hyaline cartilage is produced and then replaced by bone

Answer 45

Endochondral ossification

Question 46

___ refers to the synthesis of bone from an embryonic tissue called mesenchyme

Answer 46

Intramembranous ossification

Question 47

___ is a disk of hyaline cartilage that is actively being produced by chondrocytes during growth in long bones

Answer 47

Epiphyseal plate