Session 1 - Homeostasis and Examining Cells

Question 1

What effect does Interleukin 6 (IL-6) have on body temperature? Why?

Answer 1

It increases the core body temperature set point in the hypothalamus. This initiates heat generation and raises the body temperature to a point where the immune system can work optimally

Question 2

What is Pyrexia?

Answer 2

A fever (Core Body Temperature above 38.5’C)

Question 3

What is the normal range of blood pH and why.

Answer 3

Normal - pH 7.4

Arteries - pH 7.45
Veins - pH 7.35

Variation due to CO2 concentration

Question 4

What are the symptoms of Acidosis

Answer 4

Headaches, Confusion, Tiredness, Tremors, Coma

Question 5

What are the 2 main causes of acidosis?

Answer 5

Metabolic Acidosis - increased lactic acid production or inability to excrete acid via kidneys
Respiratory Acidosis - increased CO2 conc. due to HypOventilation

Question 6

What is the normal range of Core Body Temperature and why may this vary?

Answer 6

37’C +/- 0.5’C

Varies with circadian rhythm (lowers when sleeping), menstrual cycle can cause increased variation.

Question 7

Give an example of a typical Antacid

Answer 7

Aluminium Hydroxide

Question 8

What change in pH results in a positive double of the concentration of H+ ions

Answer 8

Negative 0.3 change in pH

Question 9

1) What are the 2 main ways pH is regulated?

2) What are the 2 main buffer systems?

Answer 9

1) Lungs - Respiratory Balance and Kidneys - Metabolic Balance

2) Extracellular - Carbonic Acid/Bicarbonate Buffer
Intracellular - Sodium Phosphate Buffer

Question 10

How is water distributed in the body?

Answer 10

Average Male (70kg)
TBW - 60% = 42L
ICF - 2/3 TBW (28L) : ECF - 1/3 TBW (14L)
Interstitial Fluid - 3/4 ECF (10.5L) : Plasma Volume - 1/4 ECF (3.5L)

Question 11

What is the standard osmolality of body fluids and what are the main contributors to this?

Answer 11

≈ 280 mOsm/kg

Glucose 190 mOsm/kg
Sodium Chloride (Na = 40 & Cl = 40)

Question 12

What is more frequently used osmolarity or osmolality? What is the difference?

Answer 12

Osmolality is more frequently used now. It has units mOsm/KG where as osmolarity is mOsm/Litre

Question 13

What are the 4 types of tissue?

Answer 13

1) Epithelial
2) Muscle
3) Nerve
4) Connective

Question 14

Name the most common form of permanent fixation? What is this (conc.) and why? Name another form of fixation, non-permanent.

Answer 14

Fixative Formalin - 37% Formaldehyde, 0.9% Sodium Chloride (isotonic solution) to allow for better formaldehyde penetration.

Frozen Section

Question 15

How does formaldehyde act as a fixative?

Answer 15

Reacts with amino groups on amino acids within proteins and forms a methylated bridge between protein chains.

Question 16

What is the role of the Nucleolus?

Answer 16

Site of the Ribosomal RNA synthesis

Question 17

What are cisternae?

Answer 17

Flattened sacs (associated with SER or Golgi apparatus)

Question 18

Why do mitochondrial diseases follow a female lineage?

Answer 18

Inherit all your mitochondria from your mother

Question 19

What is the role of peroxisomes?

Answer 19

Site of peroxide production. H2O2 is used to oxidise other substrates like phenols, formic acid, formaldehyde and alcohol.

Question 20

What is the main role of intermediate filaments?

Answer 20

To hold a cell together and prevent lysis. This is done by forming a tough supporting mesh work within the cytoplasm which is anchored to desmosomes

Question 21

What type of proteins are dynein and kinesis?

Answer 21

They are attachment proteins that are able to bind to organelles and move structures along microtubules.

Question 22

What is the primary role of microtubules?

Answer 22

Provide a network of highways within the cell that allow for the move movement of molecules and organelles to distant parts of the cell.

Question 23

What is the primary role of micro filaments?

Answer 23

They are dynamic and allow for a cell to contract and change shape. Eg. Cilia on microvilli to move and propel intestinal contents.

Question 24

What are 5 stages in preparing a biopsy for H&E staining?

Answer 24

1) Fixation
2) Embedding
3) Clearing
4) Staining
5) Dehydration