D.5 Hormones

Question 1

Endocrine vs Exocrine glands

Answer 1

Endocrine:
- Secrete into blood

Exocrine:
- Produced to outside of body

Question 2

Hypothalamus

Answer 2

Pituitary gland:
* Anterior and posterior lobes (connected by secretory cells)

• Recieves info from nerves
• Secrete neurochemicals –> target anterior lobe
• Secrete hormones (ADH and Oxytocin) into bloodstream

Question 3

Anterior lobe

Answer 3

• Releasing releasing factors to cause endocrine cells to release hormones into the bloodstream
• GnRH (Gonadotropin Releasing hormone) triggers LH and FSH

Question 4

Posterior lobe

ADH and Oxytocin

Answer 4

• Release hormones produced by the hypopthalamus
• Neurosecretary cells extend into the posterior lobe and release hormones into blood

ADH target kidney cells
Oxytocin target mammary glands

Question 5

Function of hormones

Answer 5

Metabolism:
- TSH (Thyroid stimulating hormone) activates thryroxin

Adult Development:
- eg. LH starts ovulation
- FSH maintain follicle growth

Reproduction:
- LH + FSH control menstration

Growth:
- GHRH triggers body growth of limbs

Equilibrium:
- ADH, released when body fluids are hypertonic and triggers reabsorption of water

Question 6

Athletes taking taking growth hormones

Answer 6

Peptide hormones:
- Produced in the anterior pituitary gland
- Target receptor cells in the liver
- Stimulates insuline

Affects:
- Bone and cartilage growth
- Muscle mass increases, but NOT strength
- Increases muscle recovery

Question 7

Milk Secretion

Prolactin and Oxytocin

Answer 7

Prolactin:
- Development of mammary glands & milk production
- Secreted by the anterior pituitary gland due to prolactin releasing hormone (PRH) from the hypothalamus
- It is inhibited by progesterone –> preventing milk production

Oxytocin:
- Positive Feedback loop => the sucking on the teet promotes oxytocin production
- Produced by the hypothalamus and promotes the milk releasing process from the mammary glands

Question 8

Steroid Hormones

Answer 8

• secreted by the adrenal cortex, testes, and ovaries
• transported through the bloodstream to the cells of various target organs
• lipophilic (fat-loving)

Question 9

Steroid Hormones

Answer 9

• secreted by the adrenal cortex, testes, and ovaries
• transported through the bloodstream to the cells of various target organs
• lipophilic (fat-loving)

Question 10

Steroid hormones fortming a receptor-hormone complex

Answer 10

bind to a steroid receptor in either the cytoplasm or nucleus of the target cell

forming an active receptor-hormone complex (the receptor complex is a protein)

the active complex then moves into the nucleus and binds directly to DNA –> and acts as a transcription factor for gene expression

Question 11

receptor-hormone complex promoting the transcription of specific genes

Answer 11

1. hormone-receptor Complex travels into the nucleus and binds to a receptor on chromatin
2. hormone-receptor complex starts production of mRNA through transcription
3. The mRNA molecules are then modified and transported to the cytoplasm. The mRNA molecules code for the production of proteins through translation.

Question 12

Peptide Hormones

Answer 12

• Peptide hormones are hydrophilic and lipophobic (fat-hating and water loving)
• Constructed from short amino acid chains
• they don’t enter the cell
  –> they just bind to receptors causing a relay of actions that leads to a gene being transcribed for a specific reason

Question 13

Process of a peptide hormone binding to a receptor on the target cells membrane

Answer 13

1. The peptide hormones bind to a receptor on the cells surface called the G-coupled receptor
2. The receptor complex centre then activates second messengers to initiate cellular activity
3. Secondary messengers are molecules that relay the received signals at the receptors on the surface of the cell
4. With signal transduction, secondary messengers initiate cell activity, the active cells are initiated in the nucleus creating a cellular response.