Musculoskeletal System: Vertebrae, Ribs and Body Segments

Question 1

what does the axial skeleton consist of?

Answer 1

vertebrae, ribs, sternum and skull

Question 2

what does the appendicular skeleton consist of?

Answer 2

limbs and girdle

Question 3

what is the role of the axial skeleton?

Answer 3

to protect CNS (spinal cord and brain) and viscera (thoracic and abdominal), breathing movement, support and movement.

Question 4

in how many places do the vertebrae articulate with each other?

Answer 4

2 places - between the bodies (via intervertabral discs) and between the arches

Question 5

what protects the spinal cord?

Answer 5

neural arches

Question 6

small spaces between the articulating vertebrae allow the exit of what from the spinal cord?

Answer 6

spinal nerves

Question 7

how many cervical (neck) vertebrae are there?

Answer 7

7

Question 8

what are some characteristics of cervical vertebrae?

Answer 8

small, no free ribs, low weight bearing, the first 2 cervicals (atlas and axis) are specialised to allow head movement.

Question 9

what are the first two cervicals called?

Answer 9

atlas and axis

Question 10

how many thoracic vertebrae are there?

Answer 10

12

Question 11

what are some characteristics of thoracic verterbrae?

Answer 11

medium sized, rib bearing (12 pairs of ribs)

Question 12

how many lumbar vertebrae are there?

Answer 12

5

Question 13

what are some characteristics of lumbar vertebrae?

Answer 13

large, high weight bearing, no free ribs

Question 14

how many sacral vertebrae are there?

Answer 14

5

Question 15

what are some characteristics of sacral vertebrae?

Answer 15

large, fused into a single mass to support weight of body and pelvis

Question 16

how many coccygael (tail) vertebrae are there?

Answer 16

1-2

Question 17

what are some characteristics of coccygael vertebrae?

Answer 17

tiny and vistigal

Question 18

which is the part of the spinal cord that is most often damaged in humans?

Answer 18

lumbar region

Question 19

where is the lumbar region in a human?

Answer 19

it lies between the thorax and pelvis

Question 20

what is osteoporosis?

Answer 20

when the lumbar region collapses which crushes the lumbar spinal nerves leading to pain in the back and legs

Question 21

what is the function of osteoblasts and osteoplasts?

Answer 21

remove and replace bone cells

Question 22

what are axial muscles?

Answer 22

intercostal muscles, abdominal wall muscles, deep back muscles

Question 23

where would you find epaxial muscles?

Answer 23

above/dorsal to the ribs

Question 24

where would you find hypaxial muscles?

Answer 24

below/ventral to the ribs

Question 25

what do epaxial muscles do?

Answer 25

extend spine

Question 26

what do hypaxial muscles do?

Answer 26

flex spine

Question 27

does flexion increase or decrease the angle between structures?

Answer 27

decrease

Question 28

does extension increase or decrease the angle between structures?

Answer 28

usually increase

Question 29

in early vertebrate ancestors that had no vertebrae, what structure stiffened the body?

Answer 29

the notochord - a flexible mesodermal rod

Question 30

in early vertebrate ancestors, where did the notochord lie?

Answer 30

immediately below the nerve cord

Question 31

what does the notochord form in humans?

Answer 31

nucleus pulposus - the core of the vertebral column

Question 32

what does the paraxial mesoderm form?

Answer 32

somites

Question 33

what do somites split into?

Answer 33

sclertome and dermomyotome

Question 34

what happens to sclerotomal cells?

Answer 34

sclerotomal calls break away from the somite and wrap around the notochord and neural tube, forming vertebrae

Question 35

what happens to dermomoyotome?

Answer 35

breaks into dermatome and myotome

Question 36

what does dermatome form?

Answer 36

epidermis of skin

Question 37

what does myotome form?

Answer 37

skeletal muscle

Question 38

what provides shock absorption in the spinal cord?

Answer 38

nucleus pulposus

Question 39

what herniates in a slipped disc?

Answer 39

the nucleus pulposus

Question 40

what does the myotome split into?

Answer 40

into dorsal (epimere) and ventral (hypomere) parts. forms epaxial and hypaxial muscles respectively. hypomere also forms limb muscles.

Question 41

what are the three layers of intercostal muscles?

Answer 41

external, internal and innermost

Question 42

what are the three layers of abdominal muscle?

Answer 42

external, internal and transverse

Question 43

what forms BLOCKS of muscle and skin?

Answer 43

the dermomyotome of somites

Question 44

what forms vertebrae (a series of repeating units)?

Answer 44

sclerotome

Question 45

where is residual segmentation most obvious in adults?

Answer 45

in the thorax: intercostal muscles of chest wall; segmental pattern of blood vessels; segmental nerves to muscles and skin; ribs, vertebrae and sternal elements.

Question 46

what do vertebrate animals show variation in?

Answer 46

vertebral numbers (no of segments = somites) and vertebral regionalisation (specification of segment identity)

Question 47

how many cervical vertebrae do mammals have?

Answer 47

7

Question 48

mammals developed a rib-less lumbar region. what does this allow?

Answer 48

greater dorsoventral flexion of the spine

Question 49

What controls the anteroposterior axis during development?

Answer 49

hox genes