Lecture 7 Cell-cell communication and signal transduction within cells

Question 1

What are the 3 classes of hormones, in terms of what they are made up of?

Answer 1

Polypeptide/protein hormones - insulin
Amine hormones - adrenaline
Steroid hormones - estrogen

Question 2

What are the 3 ways that cells communicate?

Answer 2

1 - They secrete chemicals that signal cells some distance away - hormones
2- They display plasma-membrane bound signalling molecules that influence other cells upon direct contact
3 - They form gap junctions that directly join the cytoplasms of interacting cells.

Question 3

What are the 2 parallel systems for the regulation and integration of bodily functions?

Answer 3

Endocrine system - hormones, regulate from a distance

Nervous system - Acts via neurotransmitters, physical contact.

Question 4

What are the autocrine, paracrine and endocrine hormone systems?

Answer 4

Autocrine - hormone operates on the same cell that released it
Paracrine - Message goes to a limited area in the vicinity. Message not stable
Endocrine - Messenger is secreted then travels to target cell at a distance.

Question 5

Name 6 major endocrine glands.

Answer 5

Hypothalamus
Pituitary
Thyroid
Adrenals
Pancreas
Ovaries/Testes

Question 6

In terms of the hierarchy of the endocrine glands, where does the process start? What are first targets? Second targets? Ultimate targets?

Answer 6

It starts in the hypothalamus from input from the CNS.
The first target is the anterior pituitary.
The second targets are the adrenal cortex, thyroid and Ovaries/testes
The ultimate targets are muscles, gut, liver, reproductive organs etc, pretty much anything that needs something changed.

Question 7

Name 7 physiological properties of hormones.

Answer 7

1 - Produced in small amounts by endocrine glands
2 - Secretion rate is determined by the need for that hormone
3 - Have no direct effect on the organs secreting them
4 - May exert effects on cells throughout the organism or they may act on specific target cells in certain organs
5 - Effect on tissues is largely determined by the capacity of the tissue to respond and the amount of hormone present
6 - Act as trigger substances, initiating biochemical reactions
7 - Although they have specific effects on cells, many have a number of effects.

Question 8

Name 3 examples of each class of hormone.

Answer 8

Steroid hormones - sex steroids, glucocorticoids, mineralocorticoids
Peptide hormones - Insulin, glucagon, growth hormone
Amine hormones - adrenaline, noradrenaline, thyroid hormone

Question 9

Name 2 types of adrenocortical steroids.

Answer 9

glucocorticoids

mineralocorticoids

Question 10

Name 2 types of gonadal steroids.

Answer 10

Androgens

Estrogens

Question 11

What are all steroid hormones a derivative of?

Answer 11

They are all derived from a sterane which has a completely hydrogenatedphenanthrene (3 fused benzenes) structure attached to a cyclopentane.