Topic 5a - Homeostasis...

Question 1

What internal conditions are under homeostatic control?

Answer 1

[gases] eg. O2, CO2
temp
[salt]
pH

Question 2

Ectotherms…?

Answer 2

fish, reptiles, amphibians

Question 3

Endotherms…?

Answer 3

mammals, birds

Question 4

Behavioural mechanisms in ectotherms…?

Answer 4

sunbaking & burrowing

Question 5

Behavioural mechanisms in endotherms…?

Answer 5

shivering, elevating metabolic rate, sweating/panting

Question 6

Re. thermoregulation in humans, what are the 2 phases?

Answer 6

phase 1 - behavioural

phase 2 - physiological

Question 7

What are examples of human physiological phases of thermoregulation in response to decreased & increased core temperature…?

Answer 7

Decreased temp - vasoconstriction, increased metabolic rate, shivering, hair raised
Increased temp - vasodilation, decreased metabolic rate, sweating, hair lowered

Question 8

What structures comprise the integumentary system?

Answer 8

skin, hair, nails, sensory receptors, various glands

Question 9

What structures comprise the endocrine system?

Answer 9

hormone-secreting glands & organs including hypothalamus, pituitary, thyroid, pancreas, adrenals, ovaries, testes

Question 10

What are the 4 tissue types?

Answer 10

Epithelial
Connective
Muscle
Nervous

Question 11

What is epithelial tissue…?

Answer 11

Sheets of tissue lining the external & internal surfaces of the body:
skin
lining of GIT
lining of circulatory system

Question 12

What’s under epithelial tissue?

Answer 12

proteinaceous basement membrane

Question 13

Cells lining the lungs…?

Answer 13

Simple epithelium - flattened cells & basement membrane

Question 14

Cells lining the trachea…?

Answer 14

Simple epithelium - mucous-producing cells with cilia & basement membrane

Question 15

Cells lining the skin…? (outer to inner)

Answer 15

Stratified epithelium - dead cells, flattened dying cells, differentiating cells, dividing cells, basement membrane

Question 16

Characteristics of connective tissue…?

Answer 16

lots of fluid & proteins (mainly collagen)

Question 17

Connective tissue embedded in the … component?

Answer 17

fluid

Question 18

What are the 3 main types of connective tissue?

Answer 18

• loose (forms membranes with epithelial cells)
• dense (ligaments & tendons)
• specialised (cartilage, bone, adipose, blood etc)

Question 19

Different muscle tissues…?

Answer 19

skeletal
cardiac
smooth

Question 20

In nerve tissue, … provides support & produces … that controls propagation of electrical signals?

Answer 20

glial cells provide support & produce insulation (myelin)

Question 21

Organs are…?

Answer 21

composed of at least 2 types of tissue that function together (usually all 4 tissue types are found)

Question 22

Tissue cells of the epidermis contain…? (most superficial layer)

Answer 22

dead cells

living epidermal cells

Question 23

What lies within the dermis…? (middle layer) (think skin diagram)

Answer 23

hair follicles, sebaceous gland, sensory nerve endings, sweat glands, muscle (pulls hairs upright), arterioles & venules

Question 24

What lies in the subdermal & connective & adipose tissue layer? Bottom layer

Answer 24

adipose and vasculature

Question 25

Different forms of cell-cell communication...?

Answer 25

direct synaptic paracrine endocrine

Question 26

Outline direct communication... eg?

Answer 26

cells in direct contact ions flows to and fro via gap junctions eg. cardiac cells

Question 27

Outline "remote" communication...

Answer 27

- mediated by chemicals released by one cell type & received by another - receptor proteins in target cells bind to chemical signal - secreted substances only influence target cells

Question 28

Example of synaptic communication...?

Answer 28

neurotransmitters that transmit signals from cell to cell

Question 29

Outline paracrine hormones... eg?

Answer 29

chemicals released cause response in nearby cells - localised & short-lived eg. prostaglandins

Question 30

Outline endocrine hormones... eg?

Answer 30

chemicals secreted into the bloodstream - target cells can be far away from secreting cells effects can be long or short-lived eg. insulin

Question 31

3 main classes of hormones...? eg?

Answer 31

peptides (eg. insulin) modified AAs (Noradrenaline) steroids (testosterone)

Question 32

2 basic types of hormonal response mechanism...?

Answer 32

peptide & modified AAs | steroids

Question 33

Describe how peptide & modified AA hormones work...

Answer 33

bind to receptor on membrane of target cell -> activates 2nd messenger system (cAMP) -> activates other enzymes -> enzymes catalyse specific reactions -> product

Question 34

Describe how steroids hormones work...

Answer 34

diffuses thru plasma membrane -> binds to receptor in nucleus (or to one in cytoplasm that carries it into nucleus) -> hormone-receptor complex binds to DNA & causes RNA polymerase to bind to promoter site for gene -> transcription (DNA -> mRNA) -> mRNA fucks off into cytoplasm, attaches to ribosome & synthesises specific protein