chapter 8 - purely skeletal system

Question 1

list the functions of the skeleton

Answer 1

1. provides a scaffold to support the weight of the rest of the body
2. facilitates movement by being points of attachment for muscles
3. protection of vital internal organs
4. produces RBC’s
5. stores and releases minerals and fats

Question 2

how many bones make up the adult human skeleton?

Answer 2

206

Question 3

what are the two sections that bones of the skeleton are divided into?

Answer 3

the axial skeleton and the appendicular skeleton.

Question 4

what is the axial skeleton?

Answer 4

bones that lie around the central axis of the body

Question 5

what is the appendicular skeleton?

Answer 5

bones of the upper and lower limbs

Question 6

what are the 5 different types of bones?

Answer 6

• long bone
• short bone
• irregular bone
• flat bone
• sesamoid bone

Question 7

long bone

Answer 7

supports weight and allows movement

eg. femur

Question 8

short bones

Answer 8

provide stability and some movement

eg. intermediate cuneiform, lateral cuneiform, medial cuneiform

Question 9

irregular bone

Answer 9

variable nature helps to protect different structures

eg. vertebrae

Question 10

flat bone

Answer 10

protects internal organs

eg. sternum

Question 11

sesamoid bone

Answer 11

protects tendons

eg. patella

Question 12

what are the three distinct parts of long bones

Answer 12

1. diaphysis - shaft making up the main portion of the bone - cavity acts as a fat storage sight and is called the yellow bone marrow. (WBC’s are produced here)
2. epiphyses - enlarged ends of the bone, covered in a thin layer of cartilage. compact bone on outside but spongy/ cancellous bone on the inside. (RBC’s are produced here)
3. periosteum - dense, white, fibrous outer covering of the bone.

Question 13

microscopic structure of bone

Answer 13

• bone is classified as a connective tissue (cells separated from each other by large amounts of non-cellular material called matrix)
• in bone, inorganic salts of calcium and phosphate are deposited in the matrix, increasing its rigidity and strength.

Question 14

microscopic structure of compact bone

Answer 14

the consist of units called osteons, which run parallel to the long axis of the bone, giving the bone maximum strength.

description: consist of osteons with concentric layers of lamellae.

Question 15

microscopic structure of spongy bone

Answer 15

also called cancellous bone

it consists of thin, bony, irregular plates called trabeculae

• bone cells occupy spaces in the trabeculae, and nerves and blood vessels pass through irregular spaces in the matrix.

Question 16

structure of cartilage

Answer 16

it is a connective tissue

it contains numerous fibres made up of a protein called collagen. these fibres are embedded in a firm matrix of a protein-carbohydrate complex called chondrin.

Question 17

what does chondrin do for the bone?

Answer 17

chondrin allows cartilage to function as a structure of support.

Question 18

what does collagen do for the bone?

Answer 18

the presence of collagen fibres gives the cartilage a certain degree of flexibility.

Question 19

explain the process of cells maturing, becoming chondrocytes

Answer 19

cartilage has a firm matrix in which collagen fibres are embedded. within the matrix are spaces that contain cartilage cells called chondroblasts.

• these cells produce matrix and gradually become surrounded until they are surrounded in small spaces called lacunae.
• once this has occurred, the cells are considered to be mature and called chondrocytes

Question 20

what are the three types of cartilage?

Answer 20

hyaline cartilage, elastic cartilage and fibrocartilage

Question 21

describe hyaline cartilage and provide an example

Answer 21

• so fine that they’re not distinguishable under a light microscope
• closely packed fibres throughout the matrix

eg. rings of the trachea and bronchi + articular cartilage

Question 22

describe elastic cartilage and provide an example

Answer 22

• clearly visible elastic fibres and very fine collagen fibres (like hyaline), but not so closely packed
  eg. external ear

Question 23

describe fibrocartilage and provide an example

Answer 23

• parallel bundles of thick collagenous fibres make up the tissue, causing its coarse appearance
• not as compact as hyaline cartilage and able to be compressed slightly

eg. intervertebral discs in the spinal column, meniscus of the knee joint, tissue joining two sides of the pelvis

Question 24

additional facts about cartilage

Answer 24

• does not contain blood vessels
• all nutrition and waste removal from the cells depends on diffusion through the matrix
• this is a slow process and the reason why some injured cartilage takes some time to heal

Question 25

joints are classified according to...?

Answer 25

- the range of movement they allow (functional classification) - the type of connective tissue that binds the bones together (structural classification)

Question 26

what are the three types of joints?

Answer 26

fibrous, cartilaginous and synovial

Question 27

what are fibrous joints?

Answer 27

(immoveable) - no movement occurs between the bones - bones held in place by fibrous connective tissue eg. skull or between the teeth and jaw

Question 28

what are cartilaginous joints?

Answer 28

(slightly moveable) - held in place by cartilage, allowing slight movement eg. junction of the two pelvic bones (pubis symphysis), joints between adjacent vertebrae, joints between ribs and sternum

Question 29

what are synovial joints?

Answer 29

(freely moveable) - amount of movement is limited by ligaments, muscles, tendons and adjoining bones eg. shoulder, elbow, wrists, fingers, hips, knees, ankles and toes

Question 30

types of synovial joints

Answer 30

- ball and socket joints - hinge joints - pivot joints - gliding joints - saddle joints - condyloid joints

Question 31

ball and socket joints

Answer 31

- when the spherical head of one bone fits into a cup-like cavity of another - eg. head of the humerus fits into a depression in the scapula or head of the femur articulates with the pelvis

Question 32

hinge joints

Answer 32

- allow movement in one plane only (like the hinge of a door) - concave surface of one bone fits into the concave surface of another - eg. the elbow and knee are the best examples - other examples include the ankle and between the bones of the fingers and toes

Question 33

pivot joints

Answer 33

- formed by rounded, pointed or conical end of one bone articulating with a ring - joint between the first vertebrae and the second vertebrae (allows the head to rotate) - between the radius and the ulna of the forearm (allowing rotation of the hand)

Question 34

gliding joints

Answer 34

- allow movement in one direction in a side to side or back and forth motion, restricted only by ligaments - found between carpal bones, tarsal bones, the sternum and clavicle, the scapula and clavicle

Question 35

saddle joint

Answer 35

- the only true saddle joint is where the thumb joins the palm of the hand - two bones forming the joint are both saddle shaped (concave in one direction and convex in the other) - fit together in such a way that they allow side to side and back and forth movements

Question 36

condyloid joints

Answer 36

- have one surface of bone slightly convex that fits into a slightly concave depression in another bone - allow movements in two directions - occur between radius and carpal bones, metacarpal bones and phalanges of fingers, between the metatarsal bones and phalanges of toes.

Question 37

what allows a synovial joint to move freely?

Answer 37

the structure of the synovial joint, including the synovial capsule, fluid and articular cartilage

Question 38

provide 4 functions of synovial fluid

Answer 38

1. lubricates 2. helps keep the articulating surfaces from making contact with each other 3. provides nourishment for the cells of the articular cartilage 4. contains phagocytic cells that remove microorganisms and debris resulting from wear and tear of a joint

Question 39

articular cartilage

Answer 39

smooth surface for movement

Question 40

articular discs (menisci in knee)

Answer 40

direct fluid to areas of a greatest friction

Question 41

bursae

Answer 41

prevent friction between a bone and a ligament or tendon and a bone and the skin where a bone inside a joint capsule is near the body surface

Question 42

ligaments

Answer 42

hold the joints together in many joints

Question 43

flexion vs extension

Answer 43

``` flexion = decreases the angle of articulating bones extension = increases the angle between articulating bones ```

Question 44

rotation

Answer 44

the movement of a bone around its long axis

Question 45

how many cervical vertebrae are there?

Answer 45

7

Question 46

how many thoracic vertebrae are there?

Answer 46

12

Question 47

how lumber vertebrae are there?

Answer 47

5

Question 48

what are the three types of ribs and how many are there of each?

Answer 48

true ribs: 7 (ribs 1-7) false ribs: 3 (ribs 8-10) floating ribs: 2 (ribs 11-12)