HB 2.3 - Intro to Human Body

Question 1

Define “Cell Division”

Answer 1

• Cells turning off certain genes permanently so that they only express genes that are related to its function -> “Committed”

Question 2

Define “Stem Cells”

Answer 2

• Undifferentiated cells with no specialised function that can endlessly self-renew and differentiate into many types of tissues

Question 3

Name the 2 types of stem cells and their potency

Answer 3

i. Embryonic Stem (ES) Cells
- Totipotent

ii. Adult Stem Cells
- Multipotent or Unipotent

Question 4

Define “Totipotent” and give an example

Answer 4

• Able to give rise to all body tissue types

- Inner Cell Mass

Question 5

Define “ Multipotent” & “Unipotent” and give an example

Answer 5

i. Multipotent
- Able to differentiate to >1 cell types or lineage
- Hematopoietic Stem Cells; Hair Follicle Stem Cells

ii. Unipotent
- Able to differentiate into x1 cell type
- Epidermal Stem Cells; Liver Stem Cells

Question 6

What is the “Immortal Stand Hypothesis”

Answer 6

• The theory that stem cells undergo asymmetric division to endlessly self-renew

(Asymmetric division = Old DNA remains the same stem cell type; New replicated DNA differentiates into a more specialised cell

Question 7

What are the 4 tissues categories?

Answer 7

i. Epithelial Tissue
ii. Connective Tissue
iii. Muscle Tissue
iv. Nervous Tissue

Question 8

What is the function(s) of Epithelial Tissue? Where is it derived from?

Answer 8

• Derived from all x3 germ layers
• Function:
  i. Sheets of cells that lines the external of body; internal body cavities; inside of lumen
  ii. Form some glands
  iii. Provide a dynamic barrier for import and export of molecules

Question 9

What is the function(s) of Connective Tissue?

Answer 9

• Provides support and protection
• Connects organs and tissues
• Exist as matrix (extracellular material produced by connective tissue cells)

Question 10

What are the types of connective tissue? List the categories of each types.

Answer 10

x3 types of connective tissue:

i. Connective Tissue Proper
- Loose Connective Tissue (Areolar; Adipose; Reticular)
- Dense Connective Tissue (Regular elastic; Irregular elastic)

ii. Supportive Connective Tissue
- Cartilage (Hyaline; Fibrocartilage; Elastic)
- Bone (Compact bone; Spongy bone)

iii. Fluid Connective Tissue
- Blood
- Lymph

Question 11

List the 4 types of muscle tissues and their characteristics.

Answer 11

i. Skeletal Muscle Cell
- Striated
- Voluntary Movement
- Multi-nucleated on the boundaries
- Derived from mesoderm

ii. Cardiac Muscle Cell
- Striated (organised/ visible)
- Involuntary Movement
- Single-central-nucleated
- Derived from mesoderm

iii. Smooth Muscle Cell
- Non-striated
- Involuntary Movement
- Single-stretched-central-nucleated
- Derived from mesoderm

iv. Myoepithelial Cell (on epithelia: for iris muscle dilation; secretion of saliva, sweat, milk from glands)
- Non-striated
- Involuntary Movement
- Single-central-nucleated
- Derived from ectoderm

Question 12

What is nervous tissue?

Answer 12

• Excitable cells

- Conducts electrochemical signals

Question 13

List the types of nervous cells and their function.

Answer 13

i. Neurons
- Sends electrochemical signals

ii. Neuroglia
- Supports neurons, modulates information propagation

Question 14

List the 2 types of tissue membrane.

Answer 14

i. Epithelial Membrane
- Epithelium that attaches to a layer of connective tissue
- Includes Mucous; Serous; Cutaneous membranes

ii. Connective Tissue Membrane
- Formed from connective tissue
- Enclose organs and line movable joints

Question 15

Define “Compartmentalisation”

Answer 15

• A general principle that compartments of the body parts are separated by membranes that act as barriers.

Question 16

Define “Homeostasis”

Answer 16

• Maintaining a dynamic stable internal environment that is within narrow limits to ensure cell survival. The overall unchanged variable is achieved without using energy.

Question 17

List examples of factors that homeostasis regulates

Answer 17

• [Nutrient Molecules]
• [O2] & [CO2]
• [Waste Products]
• pH Level
• Amount of H2O, [Salt] & [Electrolytes]
• Volume & Pressure
• Temperature

Question 18

Why do pH level have to be regulated?

Answer 18

• Different proteins can only work under certain pH range

Question 19

What is the range and average arterial blood pH level?

Answer 19

• Range: 7.35 - 7.45

- Average: 7.40

Question 20

What is acidemia?

Answer 20

pH level being too low

Question 21

What is alkalemia?

Answer 21

pH level being too high

Question 22

Name 4 types of acidemia

Answer 22

i. Ketoacidosis
- (eg. in type I diabetes) ↓ insulin -> Use fat as fuel -> Acidic ketone produced

ii. Latic Acidosis
- (eg. too much exercise; Heart failure) ↓[O2] -> ↑Latic acid produced

iii. Renal Tubular Acidosis
- Damaged kidneys can’t remove excess acid -> too much acid in blood

iv. Hyperchloremic Acidosis
- (eg. severe diarrhoea; kidney disnease) ↓[Bicarbonate] = Can’t buffer pH

Question 23

Define “enzyme”

Answer 23

• A biological catalyst used to speed up and control rates of biochemical reactions by providing an alternative pathway with a lower activation energy
• ↑ reaction rate by up to 10^19

Question 24

Define “isoenzyme”

Answer 24

Enzymes that have different amino acid sequences, kinetic/ physical/ chemical properties & tissue distributions but targets the same substrate and make the same product

Question 25

Define “Vmax”

Answer 25

• Maximal rate of reaction

- Directly proportional to [total enzyme] thus = velocity with saturated substrate

Question 26

Define “Km”

Answer 26

• The Michaelis Constant, shows the affinity of enzyme for substrate and shows the enzyme specificity
• ↑Tightly bind = ↑Affinity = ↓Km
• The amount of substrate that binds 1/2 of available enzyme, thus produces 1/2 of maximum velocity (Vmax)