D5 Hormones and Metabolism

Question 1

Endocrine System

Answer 1

Hormones are secreted from endocrine glands
Into the bloodstream
Pancreas, pituitary, thyroid.

Question 2

Exocrine System

Answer 2

Digestive enzymes and sweat are secreted by exocrine glands
Through a duct into a specific location
Pancreas, Skin

Question 3

Endocrine glands and their location

Answer 3

Pituitary (brain)
Thyroid (neck)
Adrenal (kidney)
Pancreas (gut)
Testes (male abdomen)
Ovaries (female abdomen)

Question 4

Steroid Hormones

Answer 4

Are able to get across the cell membrane & bind to a receptor protein.
Forming a receptor hormone complex, which enters the nucleus through a nuclear pore
Binds to a gene and acts as a promoter
Steroid hormones are lipids (made from cholesterol)
Because they are lipids (non-polar) they can pass easily into a cell through the lipid bilayer of the membrane

Examples: Testosterone and Estrogen
Other examples can include performance enhancing drugs (PED)
Illegally used by athletes
Increase muscle mass, strength and speed.
Can have side effects, like acne, vision problems, high blood pressure, insomnia and disqualification from competition.

Question 5

Steroid Hormones in action

Answer 5

1) A steroid hormone enters the cell directly through the lipid bilayer of the cell membrane
2) The steroid hormone binds to a receptor protein in the cytoplasm to form a receptor-hormone complex
3) The receptor-hormone complex enters the nucleus through a nuclear pore
4) The receptor-hormone complex binds to a specific gene on DNA and activates this gene (promotes transcription)
5) mRNA molecules are transcribed from this gene
6) Ribosomes translate this mRNA into a new polypeptide

Question 6

Peptide Hormones

Answer 6

Binds to a receptor protein in the plasma membrane and initiates a series of responses
Secondary messenger is initiated and takes the message to more messenger molecules
The final messenger molecule can enter the nucleus through the nuclear pores
Promotes or suppresses genes

Peptide hormone are composed of polypeptides (proteins)
They cannot pass into the cell
Examples: insulin and ADH

Question 7

Peptide Hormones in action

Answer 7

1) Peptide hormones binds to a receptor protein on the target cell’s outer membrane
2) A secondary messenger molecule in the cytoplasm is triggered into action
3) The secondary messenger molecule chemically activates one or more messenger molecules in the cytoplasm

The final messenger molecule will either
4.1) Activate an enzyme in the cytoplasm to initiate a reaction that couldn’t have occurred without being initiated by the hormone
4.2) Activate a transcription factor that enters the nucleus and either promotes or inhibits transcription and protein production (turns a gene off or on)

Question 8

The Pituitary Gland

Answer 8

Stuck to the hypothalamus
Anterior - front of head
Posterior - butt

Question 9

Posterior Pituitary Secretion

Answer 9

Contains the axons of the neurosecretory cells that originate in the hypothalamus
Hormones are produced in the hypothalamus, move along the axon into the posterior pituitary, and are secreted by the posterior pituitary in a way similar to how neurotransmitters are released.

Question 10

Anterior Pituitary Secretion

Answer 10

Neurosecretory cells are entirely within the hypothalamus
Hormones are released by the hypothalamus into a portal blood vessel
These are often called releasing hormones, because they trigger the release of other hormones in the anterior pituitary
GnRH
The portal blood vessel carries the hormone to their target cells in the anterior pituitary
The cells of the anterior pituitary are triggered to produce their own hormones
The hormones produced by the anterior pituitary are secreted into the bloodstream

Question 11

Produced by / Secreted by.

Answer 11

IN POSTERIOR
Produced by hypothalamus secreted by posterior pituitary
IN ANTERIOR
Produced by anterior pituitary and secreted by anterior pituitary

Question 12

Milk-producing Cells

Answer 12

During pregnancy, prolactin hormone levels increase, which causes milk-secreting cells to develop in breast tissue
After birth, prolactin causes the cells to produce milk

Question 13

Milk secretion

Answer 13

High levels of estrogen during pregnancy inhibit the secretion of milk
During birth, estrogen levels drop and the oxytocin levels rise
Oxytocin causes milk to be ejected through the nipple
Stimulation of the nipple during breast feeding causes an increase in oxytocin and prolactin (positive feedback loop), which continues milk production and secretion.

Question 14

Reproduction Hormones

Answer 14

LH and FSH trigger ovulation and follicle growth (ANTERIOR PITUITARY)

Question 15

Growth Hormone

Answer 15

GH triggers increase in rate of mitosis (ANTERIOR PITUITARY)

Question 16

Antidiuretic Hormone

Answer 16

ADH triggers reabsorption of water in the collecting duct of the kidneys. (POSTERIOR PITUITARY)