Tissues - extra

Question 1

What is the difference between phagocytosis and pinocytosis?

Answer 1

Both the engulfment of substances from the extracellular environment into the cell but phagocytosis is particles (solids) whilst pinocytosis is fluids.

Question 2

What is the cell of origin in carcinomas?

Answer 2

Epithelial cells

Question 3

What is the cell of origin in lymphomas?

Answer 3

Leukocytes

Question 4

What is the cell of origin in leukaemia?

Answer 4

Haematopoietic cells (bone marrow)

Question 5

What is the cell of origin in gliomas?

Answer 5

Glial cells (support cells of CNS)

Question 6

What is the cell of origin in neuroblastomas?

Answer 6

Neurones

Question 7

What is the cell of origin in sarcomas?

Answer 7

Mesenchymal cells (connective tissue)

Question 8

What does the basal lamina do?

Answer 8

Separates the epithelial layers with underlying connective tissue.

Question 9

What can an iron or vitamin C deficiency lead to?

Answer 9

Scurvy and under-hydroxylated collagen as they are needed for hydroxylates (the enzymes that carry out hydroxylation) to function.

Question 10

What extra thing is found on pro-collagen?

Answer 10

Propeptides on the ends (n and C terminals)

Question 11

What are the major constituents of the basement membrane?

Answer 11

• Collagen (IV)
• Laminins
• Nigoden
• Integrin
• Perlecan (proteoglycan)

Question 12

What is Marfan’s syndrome?

Answer 12

• Mutation in fibrillin-1
• Arm span is longer than height
• Predisposed to aortic ruptures due to less elasticity in blood vessels

Question 13

What is an example of the basement membrane in an organ?

Answer 13

Glomerulus in the kidney - prevents macromolecules from entering the nephron.

Question 14

What is a complication of the kidneys associated with diabetes?

Answer 14

Excessive ECM accumulation in the glomerulus, restricting renal filtration and leading to renal failure.

Question 15

What is the structure of proteoglycans?

Answer 15

A core protein with one or more glycosaminoglycan chains branching off from it.

Question 16

What does decorin do?

Answer 16

Regulates collagen fibre size and arrangement.

Question 17

How are fibronectins associated with actin?

Answer 17

Via integrin. Fibronectin binds to the extracellular region of integrin whilst actin binds to the internal region of integrin.

Question 18

What is colloid oncotic pressure?

Answer 18

Opposite to hydrostatic pressure - the pulling force inwards.

Question 19

What are the main differences between cardiac and smooth muscle?

Answer 19

• Cardiac has regular arrangement of actin and myosin (striated) and smooth muscle does not
• Contraction involves different substances in both (smooth muscle involves Ca-CAM and MLCK)

Question 20

What are the three main forms of enzyme-linked receptors?

Answer 20

• Tyrosine-linked (95%)
• Guanylyl-cyclase linked
• Serine-threonine linked

Question 21

Describe the development of melanocytes.

Answer 21

• Precursors are melanoblasts derived from neural crest cells.
• Extensive migration to the ears, skin and uveal tract (eye) as they are highly dendritic
• Steel factor (MGF) is essential for early development of melanocytes