Sesh 2: Cells And Tissue Types

Question 1

What are the 3 types of cell junction?

Answer 1

1. Tight junctions
2. Desmosomes
3. Gap junctions

Question 2

What is the main function of desmosomes?

Answer 2

To strengthen tight junctions between cells that need to resist stretching/twisting.

Question 3

What type of proteins form channels at gap junctions?

Answer 3

Connexins/connexons

Question 4

Tight junctions, desmosomes and gap junctions attach cells in the _________domain.

Answer 4

Lateral

Question 5

How can cells be attached in the basal domain?

Answer 5

1. Hemidesmosomes to basement membrane
2. Focal adhesions to basement membrane
   * Both involve the transmembrane glycoprotein integrin

Question 6

What are the 2 functions of integrins?

Answer 6

1. Attach cytoskeleton to ECM-mechanical

2. Signal transduction from ECM to cell-biochemical

Question 7

Name 2 ways in which cultured cells behave differently to when in a living body.

Answer 7

1. Contact inhibition

2. Limited lifespan- senescence

Question 8

What are the 6 methods of cell communication?

Answer 8

1. Direct-gap junctions
2. Autocrine
3. Paracrine
4. Endocrine
5. Synaptic
6. Neurocrine-e.g. In adrenal medulla and pituitary gland

Question 9

The cell bursts and dies in __________.

Answer 9

Necrosis.

Question 10

Cells shrink and die in _________.

Answer 10

Apoptosis.

Question 11

What is the relationship between cell renewal rate and cancer?

Answer 11

Higher cell renewal rate, higher risk for accumulating mutations, so higher cancer risk.

Question 12

What are the 4 main types of tissue?

Answer 12

1. Epithelial
2. Muscle
3. Nervous
4. Connective(multiple specialised types)

Question 13

What are the 6 main specialised types of connective tissue?

Answer 13

1. Adipose
2. Lymphatic
3. Blood
4. Haematopoietic
5. Cartilage
6. Bone

Question 14

What are epithelioid cells?

Answer 14

Epithelial cells without a free surface/polarity. E.g. Islets of Langerhans, parenchyma of adrenal gland.

Question 15

What domain of epithelial cells is often specialised?

Answer 15

Apical

Question 16

What is normal plasma osmolality?

Answer 16

290 mOsmol/kg. Lower value=more dilute

Question 17

What is the osmolality of normal saline?

Answer 17

300 mOsm/kg (150mmol/L Na+ and 150 mmol/L Cl-)- isotonic to plasma.

Question 18

If you give a patient a colloid solution, the water should stay in what body compartment?

Answer 18

Intravascularly-protein is too big to leave blood.

Question 19

Water moves to areas of ____ oncotic pressure.

Answer 19

High.

Question 20

What is rabdomyelitis?

Answer 20

Damage to striated muscle causing necrosis, and potassium to leak into the blood, causing hyperkalaemia.

Question 21

What are normal plasma concs of sodium and potassium?

Answer 21

1. Na=140 mmol/L

2. K=5 mmol/L

Question 22

What are the normal intracellular concs of Na and K?

Answer 22

1. Na- 14 mmol/L

2. K- 160 mmol/L

Question 23

What’s the normal range of blood pH?

Answer 23

7.35-7.45

Question 24

What are normal plasma lactate levels?

Answer 24

<2nMol/L

Question 25

Connective tissue can be broadly classified based on what 3 things?

Answer 25

1. ECM-ground substance 2. Fibres-protein 3. Cells

Question 26

Name 6 functions of connective tissue.

Answer 26

1. Connecting 2. Transporting 3. Storing 4. Protection/insulation 5. Wound healing 6. Defending

Question 27

What are proteoglycans?

Answer 27

Core proteins with covalently bound glycosaminoglycans (GAGs) that make up connective tissue ground substance.

Question 28

What is hyaluronic acid?

Answer 28

A unique GAG bound to proteoglycans by a link protein, found in cartilage ground substance.

Question 29

What type of collagen is the most abundant?

Answer 29

Type I- around 90%

Question 30

What is a disease of abnormal type I collagen?

Answer 30

Osteogenesis imperfecta

Question 31

What is a disease of abnormal elastic fibres?

Answer 31

Marfan's syndrome

Question 32

Name key features of Marfan's syndrome

Answer 32

- Arachnodactyly - Very tall - Frequent joint dislocation

Question 33

What do mast cells release?

Answer 33

1. Histamine 2. Heparin 3. Substances to attract neutrophils and eosinophils.

Question 34

What is the main role of brown fat?

Answer 34

Non-shivering thermogenesis- especially important in babies.

Question 35

What are the roles of white adipose tissue?

Answer 35

1. Fuel reserve 2. Insulation 3. Shock absorption

Question 36

Loose connective tissue mainly has a role in....?

Answer 36

Transport/diffusion of nutrients and waste products to/from epithelia.

Question 37

Give examples of structures composed of dense regular connective tissue.

Answer 37

-Ligaments -Tendons -Aponeuroses (All withstand unidirectional stress)

Question 38

Give examples of where dense irregular connective tissue is found.

Answer 38

- Deep dermis | - Intestinal mucosa

Question 39

What is osmolality?

Answer 39

A function of the concentration of particles in solution.

Question 40

What is an abnormal plasma pH commonly due to?

Answer 40

Major organ dysfunction e.g. Lungs, kidney, liver. Shock- poor tissue perfusion-->hypoxia-->acidosis

Question 41

What are the 2 main types of connective tissue proper?

Answer 41

Dense and loose.

Question 42

What are glycosaminoglycans?

Answer 42

Long chain polysachharides that attract water to form a hydrated gel- allows CT to resist compression. They are covalently bound to a core protein to form proteoglycans in the ground substance of connective tissue.

Question 43

Where can loose connective tissue be found?

Answer 43

- Surrounding small blood vessels - Associated with gland epithelium - Superficial layer of dermis - Colon submucosa