Biology Chapter 12: Musculoskeletal System and Skin

Question 1

Cartilage is made from what kind of cell

Answer 1

Chondrocytes (make up collagen)

Question 2

Collagen is found in the

Answer 2

Extracellular matrix

Question 3

Axial skeleton is made up of

Answer 3

Vertical axis including skull and vertebral column and ribs which houses the CNS

Question 4

Order the vertebrae sections from top to bottom

Answer 4

Cervical
Thoracic
Lumbar
Sacrum
Coccyx

Question 5

Number of ribs

Answer 5

12 pairs of ribs that encase heart and lungs

Question 6

Middle part of long bone

Answer 6

Diaphysis

Question 7

End of long bone

Answer 7

Epiphysis

Question 8

Growth plate is called what and where is it located?

Answer 8

And the end of the diaphysis before the epiphysis. Also called epiphyseal plate

Question 9

Example of a sesamoid bone

Answer 9

Patella (embedded in tendons

Question 10

Non cellular part of the bone is made of what

Answer 10

Collagen fibres, water and crystallized materials (hydrooxyapatite)

Question 11

Storage deposit for calcium and phosphate

Answer 11

Hydrooxyapatite

Question 12

Osteoblasts

Answer 12

Create new bone by producing osteoids

Question 13

Osteoclasts

Answer 13

Break down bone (remember “chew up” bone)

Question 14

Osteocytes

Answer 14

Most common bone cell but “least special” - retired osteoblasts

Question 15

Calcitriol is a derivative of

Answer 15

Vitamin D

Question 16

Parathyroid and calcitriol increase or decrease blood calcium levels?

Answer 16

Increase blood Ca by stimulating osteoclast activity and increase absorption of dietary calcium from digestive tract

Question 17

Calcitonin

Answer 17

Decreases blood calcium levels. Secreted from the thyroid gland. Inhibits activity of osteoclasts. Also will reduce absorption of calcium from digestive tract

Question 18

Fundamental unit of compact bone

Answer 18

Osteon

Question 19

Osteon also called

Answer 19

Haversian system

Question 20

Osteons

Answer 20

Basic unit of compact bone. Cylindrical structures composed of concentric rings or lamellae of bone matrix

Question 21

In the center of Osteon is a central channel called

Answer 21

Haversian canal

Question 22

Haversian canal houses what

Answer 22

Bone’s supply of blood and nerve supply

Question 23

In compact bone, osteocytes live in

Answer 23

Its own pocket of space called the lacuna

Question 24

Osteocytes communicate through channels running perpendicular to Haversian canal called

Answer 24

Canaliculi. Exchange nutrients and waste products through extensions of their cytoplasm via these channels

Question 25

Bone marrow is found

Answer 25

Flat bones and heads of long bones

Question 26

Red bone marrow

Answer 26

Hematopoesis (production of blood cells) produces both red and white blood cells

Question 27

Yellow bone marrow made of

Answer 27

Adipocytes, storage of fat

Question 28

The cross-bridge is currently positioned at a 90° angle to the thin filament. This moment in time occurs immediately after:

Answer 28

ATP is hydrolyzed to form ADP and inorganic phosphate. Hydrolysis of ATP into ADP and inorganic phosphate restores the myosin head to a 90° angle, “cocking” it for new attachment and the ensuing power stroke.

Question 29

Megakaryotes

Answer 29

large bone marrow cells with a large nucleus which are responsible for the production of platelets, which are necessary for normal blood clotting Also, Megakaryocytes are precursor cells that express some immune-related surface markers, like CD4, that HIV uses for entry.

Question 30

Juxtaglomerular Cells

Answer 30

These are specialized smooth muscle cells located in the walls of the afferent arterioles of the kidney. They play a role in regulating blood pressure by secreting renin in response to certain stimuli.

Question 31

The Haversian system is the fundamental structural unit of

Answer 31

compact bone

Question 32

Purpose of compact bone vs spongy bone

Answer 32

Compact bone - support (made of haversian systems - osteons) Spongy bone - reduce bone weight while maintaining strength, absorb shock and impact. HOUSES BONE MARROW

Question 33

Do adipose cells undergo high levels of mitosis

Answer 33

During adulthood, adipocytes are unlikely to undergo mitosis. While there is a limited replicative capacity of adipocytes under certain conditions, adipocytes typically respond to changing conditions by altering their size.

Question 34

Fascicle

Answer 34

bundle of muscle fibres

Question 35

Myocyte

Answer 35

= muscle cell

Question 36

Myocytes contain

Answer 36

myofibrils (rod like) which contain myofilaments of myosin and actin, organized into repeating units called sacromeres

Question 37

Sacromere

Answer 37

The basic contractile unit of a myocyte, responsible for muscle contraction.

Question 38

Sacromeres are made from what 2 filaments?

Answer 38

Myosin and actin

Question 39

Sacroplasm

Answer 39

Cytoplasm of muscle cell

Question 40

Sarcolemma

Answer 40

Plasma membrane of a muscle cell

Question 41

Sarcoplasmic reticulum

Answer 41

SMOOTH ER in muscle cell Stores Ca Direct contact with T-tubules

Question 42

Red muscle fibres

Answer 42

SLOW TWITCH (because of myoglobin)

Question 43

White muscle fibres

Answer 43

Fast twitch (less myoglobin) rely on glycolysis

Question 44

Does smooth muscle contain sacromeres?

Answer 44

NO - they are non-striated.

Question 45

Skeletal muscle is ______nucleate whether smooth muscle is _____nucleate

Answer 45

Skeletal = Multinucleate, Smooth = uninucleate

Question 46

Cardiac muscle: Nucleate? Striated?

Answer 46

Mostly, Unicleate (some are multi) Yes, striated

Question 47

Which one is myosin and which one is Actin?

Answer 47

Question 48

Name all the labelled regions

Answer 48

Question 49

How to remember z-line, m-line, H-zone, I-band, A-Band

Answer 49

Question 50

Only region that maintains length during muscle contraction

Answer 50

A Band

Question 51

Myosin binding sites are blocked by

Answer 51

tropomyosin

Question 52

What happens when Ca is present in the cell?

Answer 52

Ca binds to troponin which moves tropomyosin off the binding site on myosin

Question 53

Pathway that action potential takes in muscle cells

Answer 53

T-Tubules

Question 54

Is ATP needed for the power stroke?

Answer 54

NO ATP is needed to "cock" the myosin head (put it in a high-energy state at ~90°). But ATP is NOT needed for the power stroke itself—that movement happens when ADP and Pi are released.

Question 55

According to the cross-bridge model of muscle contraction, the muscles stiffen after death because ATP is unavailable to bind and directly release:

Answer 55

the myosin head from the actin filament.

Question 56

ACh typically causes depolarization in most cases. When does it cause hyperpolarization?

Answer 56

Acetylcholine (ACh) causes hyperpolarization in cardiac muscle cells through its action on muscarinic (M2) receptors in the heart's sinoatrial (SA) node.

Question 57

Steps of the cross bridge cycle

Answer 57

1) Ca enters cytoplasm fro SR 2) Ca binds to troponin 3) Tropomyosin is moved 4) Myosin binding site open on ACTIN 5) Myosin head (with ADP +Pi) binds to ACTIN 6) Pi released --> Power stroke 7) ADP is released. Myosin head is still attached to the ACTIN 8) ATP binds, detaching myosin from ACTIN 9) ATP is hydrolyzed, myosin head is cocked 10) Cycle repeats

Question 58

Of the following types of muscle, which are striated? I. Muscle composed of red (slow-twitch) fibers II. Muscle composed of white (fast-twitch) fibers III. Muscle lining the digestive tract IV. Cardiac muscle of the heart

Answer 58

I, II, IV smooth muscle isn't striated

Question 59

region in a sarcomere where only thick filaments (myosin) are present, without overlap with thin filaments (actin).

Answer 59

H-Band

Question 60

Contains myosin (thick filaments), with or without actin overlap. Includes both the H-zone and overlapping areas. Does not change length during contraction.

Answer 60

A Band

Question 61

Only actin (thin filaments), no myosin. Gets shorter during contraction because actin slides inward.

Answer 61

I Band

Question 62

The length of a single sarcomere can be described as:

Answer 62

the sum of half of the lengths of the two flanking I-bands and the A-band.

Question 63

A state of constant contraction

Answer 63

tentany

Question 64

Voluntary muscles may contract involuntarily due

Answer 64

reflex arc

Question 65

Which parts of the muscle are shortened during muscle contraction?

Answer 65

I band and H zone

Question 66

What's the difference between brown fat and white fat?

Answer 66

White fat stores energy (big fat droplet, few mitochondria). Brown fat burns energy to make heat (many mitochondria, has UCP1). Brown fat is metabolically active, white fat is mostly storage.