PHYL 1010 Final

Question 1

Forms of cellular communication:

Local Communication

Answer 1

Cell-to-cell communication uses physical/ chemical/ electrical communication to coordinate function within a local area/tissue

Question 2

Forms of cellular communication:

Long Distance Communication

Answer 2

Long distance signalling may involve signals passed along neurons (electrical) or through the blood-stream (endocrine)

Question 3

Forms of chemical communication:

Autocrine/Paracrine Signalling

Answer 3

Cells release signalling molecules which can regulate their own behaviour (autocrine) or that of neighboring cells (paracrine)

Question 4

Forms of chemical communication:

Neurotransmission

Answer 4

Chemical messengers are released in close proximity to the target cell. Rapid, limited dispersion

Question 5

Forms of chemical communication:

Endocrine Signalling

Answer 5

Endocrine Signalling: Chemical messengers are released into the general circulation. Slow, broad dispersion. Eg, most endocrine tissues

Question 6

Forms of chemical communication:

Neuro-endocrine Signalling:

Answer 6

Neurons release their signalling molecules into the general circulation. Slow, broad dispersion. Eg. Hypothalamic neurons

Question 7

Classes of hormones:
Lipid Soluble (lipophilic) Hormones:

Answer 7

Steroid hormones

Thyroid hormones

Question 8

Classes of hormones:
Water Soluble (lipophobic)

Answer 8

Monoamines
Peptide hormones
Protein hormones

Question 9

What is Tyrosine

Answer 9

The parents amino acid for catecholamines and thyroid hormones.
Amine hormones are synthesized from thyrosine.

Question 10

What are catecholamines

Answer 10

Made by modifying the side groups of tyrosine.
Water soluble
(Dopamine, Norepinephrine, Epinephrine)

Question 11

What are thyroid hormones

Answer 11

Synthesized from two tyrosine’s and iodine (I) atoms.

(T3 and T4) are lipid-soluble hormones

Question 12

Peptide and Protein hormones consist of

Answer 12

Long chains of amino acids.

TRH is a peptide hormone consisting of only 3 amino acids

Question 13

Growth Hormone is a

Answer 13

Protein hormone consisting of more than 200 amino acids

Question 14

Receptor-channel

Answer 14

Ligand binding opens or closes the channel

Question 15

Receptor-enzyme

Answer 15

Ligand binding to a receptor-enzyme activates an intracellular enzyme

Question 16

G protein-coupled receptor

Answer 16

Ligand binding to a G protein-coupled receptor opens an ion channel or alters enzyme activity.

Question 17

Integrin receptor

Answer 17

Ligand binding integrin receptors alters the cytoskeleton.

Question 18

What is cAMP

Answer 18

A common second messenger in the endocrine system.

Eg: all hypothalamic hormones, most pituitary hormones

Question 19

What is tyrosine kinase

Answer 19

Transfers a phosphate group from ATP to a tyrosine (an amino acid) of a protein

Question 20

Specificity

Answer 20

Ability to bind only one type of hormone

Question 21

Affinity

Answer 21

Strength of binding of hormone to its receptor

Question 22

Saturation

Answer 22

Degree to which receptors are occupied

Question 23

Up-regulation

Answer 23

Increase in receptor number due to low hormone levels

Question 24

Down-regulation

Answer 24

Decrease in receptor number due to chronic high hormone levels

Question 25

Order of a simple endocrine reflex

Answer 25

Stimulus Integrating Center Efferent Pathway Effector

Question 26

Releasing hormones

Answer 26

Hypothalamus | Pituitary

Question 27

Trophic hormones

Answer 27

``` Target endocrine glands: Thyroid Adrenal Gonads Other tissues ```

Question 28

How are the anterior and posterior pituitaries developed

Answer 28

During early embryonic development, they begin to form. Formed from an upward growth of oral ectoderm tissue (Rathkes Pouch) and downward growth of neural tissue from diencephalon.

Question 29

Giantism

Answer 29

Hypersecretion of GH before puberty

Question 30

Acromegaly

Answer 30

Hyperecretion of GH after puberty

Question 31

GH receptor defect | IGF receptor deficit

Answer 31

Defects in GH secretion or action result in reduced body size