Lecture 11 bone , Bone Marrow , Vessels And Blood

Question 1

What is one way bones can be classified and what are examples ??

Answer 1

• according to their shape
• there are 5 differently shaped bones.
• 1) flat
• 2) irregular
• 3) long
• 4) short
  5) sesamoid

Question 2

What are examples of long bone ?

Answer 2

Lower limbs bing : femur , tibia , fibula

• upper limb : radius , ulna , humerus
• small bones in fingers and toes.

Question 3

What is the function of long bones ?

Answer 3

• to facilitate movement

2) support the weight of the body

Question 4

What are examples of short bones?

Answer 4

Carpal bones in the wrist (scaphoid) and tarsal bones in the ankles ( calcaneus)

Question 5

What is one feature of long bones ?

Answer 5

-they are longer than they are wide.

Question 6

What is one feature of short bones ?

Answer 6

They are as long as they are wide .

Question 7

What are examples of flat bone ?

Answer 7

• skull ( occipital)
• sternum and ribs
• pelvis ( Illium)

Question 8

What are the functions of the flat bones ?

Answer 8

Protects internal organs

• provide large areas for attachment of muscles

Question 9

What is an example of irregular bones ?

Answer 9

Vertebrae - protects the spinal cord

• pelvis ( sacrum) : protects pelvic cavity

-

Question 10

What is an example of a sesamoid bone ?

Answer 10

Patella

Question 11

What are features of the sesamoid bones ?

Answer 11

• they are round
• they reside within tendons ( eg in the hand , feet , knees )
• only develop post Natally

Question 12

What is cancellous bone ?

Answer 12

Foundfound on the internal surface of bone , they have many spaces in between them

• also known as trabaculae

Question 13

Where is bone marrow found

Answer 13

• in between the spaces of the cancellous bone

Question 14

Where is compact bone found

Answer 14

• forms the external surfaces of bone

- comprises of 80% of skeletal mass.

Question 15

What percentage of bone marrow makes up total body mass of humans ?

Answer 15

4%.

Question 16

What are the two types of bone marrow ?

Answer 16

1) yellow bone marrow ( centre )

2) red bone marrow ( outer)

Question 17

What are 2 differences between yellow and red bone marrow ?

Answer 17

• red bone marrow has a rich blood supply , whereas yellow bone marrow has a poor blood supply due to the lack of vessels.
• red bone marrow is full of developing red blood cells whereas yellow bone marrow is full off adipocytes.

Question 18

What is the function of red bone marrow ?

Answer 18

Haemopoiesis ( production of red blood cells )

Question 19

What is the function of yellow bone marrow ?

Answer 19

• shock absorber and energy source

Question 20

what occurs in yellow bone marrow in someone who is anaemic ?

Answer 20

• yellow bone marrow is converted into red bone marrow to increase the number of red blood cells to compensate for the loss.

Question 21

How many red blood cells does the bone marrow produce a day?

Answer 21

500 billion.

Question 22

Where in the body is bone marrow primarily located ?

Answer 22

• bones of the pelvis
• sternum
• vertebrae
• ribs

Question 23

how do red blood cells enter the systemic circulation ?

Answer 23

Via permeable vasculature sinusoids within the medulla cavity

Question 24

How long does it tsake red blood cells to mature and what is their route of circulation into the heart ?

Answer 24

• 2 days

- from the venules , to the intermediate vein, larger vein to the vena cava ( it is deoxygenated currently).

Question 25

What is microcirculatiom controlled by ?

Answer 25

- precapillary sphincters - contain smooth muscle - located between arteriole and capillary - when they dilate , blood flows freely through capillary bed - when they constrict , blood is not allowed to flow through - can be used during temperature regulation

Question 26

Define a vein

Answer 26

- an elastic blood vessel that transports blood to the the heart

Question 27

Define arteries

Answer 27

Elastic blood vessels that transport blood away from the heart

Question 28

What are the three layers that make up veins ?

Answer 28

Tunica intima ( inner) - endothelial Cells Tunica media ( middle ) - elastic fibres and smooth muscle cells Tunica externa (outer)- elastic fibrous capsule

Question 29

What are two exceptions of veins that do not carry deoxygenated blood ?

Answer 29

1) pulmonary veins | 2) umbilical veins

Question 30

What is the largest vein the body ?

Answer 30

Vena cava ( inferior and superior )

Question 31

What are the four types of veins?

Answer 31

1) pulmonary veins ( carry oxygenated blood from the lungs to the left atrium) 2) systemic veins which carry deoxygenated blood from the rest of the body to the right atrium. 3) superficial veins that are located on the surface of the skin ( eg dorsal surface of the hand) and are not located near an artery 4) deep veins : located between tissues and near a corresponding artery with the same name.

Question 32

What is one difference between regular ventless and high endothelium venules ?

Answer 32

Regular venules have an endothelial layer composed of squamous endothelial cells , whereas high endothelial venules have an an endothelium made up of simple cuboidal cells.

Question 33

What are the smallest type of veins ?

Answer 33

Venules

Question 34

What is the average size of veins ?

Answer 34

1mM-1,5cm

Question 35

What are the three main layers of arteries ?

Answer 35

- tunica intima ( inner layer) : composed of an elastic membrane and smooth endothelium. - tunica media ( middle ) : smooth muscle and elastic fibres - this layer is thicker in arteries than in veins. - tunica externa ( Adventia) : collagen and elastic fibres

Question 36

Why are arteries adaptations fitted to their functions ?

Answer 36

- need to maintain Hugh blood pressure - prevents bursting of blood as blood is flowing at a very high pressure -

Question 37

Why are capillaries s adaptions fitted to their functions ?

Answer 37

- thin walls which allows diffusion of materials to happen quick - fenestrated walls allows exchange of substances - no need for strong walls as blood is flowing at a very low pressure

Question 38

Why are veins adaptions good for their functions ?

Answer 38

- valves to prevent back flow of blood - wide lumen which offers less resistance to blood flow -