15 Bone, bone marrow, vessels

Question 1

What are the types of bones?

Answer 1

long, short, flat, irregular, sesamoid

Question 2

Long bones

Answer 2

longer than they are width, normally the limbs. aid movement and support body

Question 3

Short bones

Answer 3

long as they are wide. eg wrists or ankle joints. they provide stability and aid movement

Question 4

flat bones

Answer 4

somewhat flattened, roughly parallel opposite edges.

eg occipital, thoracic cage, pelvis. protects organs and provide large areas of attachment for muscles.

Question 5

Irregular bones

Answer 5

vary in shape and structure, normally complex. eg vertebrate and sacrum. they’re there to protect organs, spinal cord, pelvic cavity and provide an anchor point for some muscles.

Question 6

Sesamoid bones

Answer 6

embedded in tendons like patella. protects tendons from stress and wear and tear.

Question 7

Types of bone tissue?

Answer 7

Cortical/compact: external surfaces.

Cancellous/spongey: network of fine bony columns. spaces filled with bone marrow

Question 8

Bone marrow. Types?

Answer 8

Aka medulla ossea
Red marrow: great blood supply, develops rbcs, found only in spongy bone. replenishes cell in the blood.
Yellow marrow: full of adipocytes, poor blood flow, shock absorber and energy source. can convert to red marrow.

Question 9

How do maturing cells leave the bone?

Answer 9

bone marrow proper has large sinosoidal capilleries. mature cells move into these and then leave the blood via the vena comitants.
megakaryocyte binds to sinosoid and release part of it into the blood and this is platelets.

Question 10

When rbc is in the circulation how long does it take to fully mature?

Answer 10

2 days

Question 11

How are capilleries controlled?

Answer 11

precapillary sphincters control flow

Question 12

Vein structure?

Answer 12

transports blood to the heart.
consists of three layers: tunica intima, tunica media, tunica externa. they have fibroelastic cartilaginous valves assist flow towards the heart.
its a low pressure system.

Question 13

vein types

Answer 13

pulmonary veins: carry oxygenated blood from lungs ti left atrium of heart.

systemic veins: carry oxygen depleted blood from body to right atrium of the hear.
Superficial veins: loacted close to surface of skin and not near corresponding artery.
Deep veins: located deep in muscle tissue and typically with a corresponding artery of the same name.

Question 14

vein sizes

Answer 14

ranges from 1 mm to 1.5cm
smallest veins: venules
largest: vena cavae.

Question 15

Arteries structure

Answer 15

elastic blood vessel that conveys blood away from the heart.
3 layers: tunica intima (non fenestrated endothelium), tunica media (smooth muscle and elastic fibres), tunica externa (collagen and elastic fibres)
smaller lumen diameter than veins

Question 16

Collateral blood vessels

Answer 16

collateral vessels provides protection for tissues that may be compromised. they provide an alternative path for arterial blood flow.
can be generation due to chronic disease such as ischaemia and sometimes produced during development.

Question 17

Vasculogenesis

Answer 17

formation of new blood vessels from angioblast precursors (bone marrow). during embryo development and newly formed cancers and endometriosis.

Question 18

Angiogenesis

Answer 18

formed new blood vessels from existing blood vessels. during fetal development, collateral arteries, postnatal lung development.

Question 19

Pericyte

Answer 19

immature smooth muscle cells, found in the basement membrane, able to differentiate into endothelial cells/fibroblasts/smooth muscles.
Function to maintain tight capillaries and prevent endothelium proliferation.