Endocrine System (hormones)

SBI4U - Howes (still missing: label the pituitary, signal cascade, transcription factors)

the two major classes of hormones

water-soluble hormones & lipid-soluble hormones

water-soluble hormones are also called __________ hormones, and lipid-soluble ones are also called __________ hormones

peptide, steroid

properties of water-soluble (peptide) hormones

• hydrophilic

• large and polar — cannot cross plasma membrane

• binds to surface receptor

properties of lipid-soluble (steroid) hormones

• hydrophobic

• can freely pass through plasma membrane (nonpolar)

• binds to a receptor within the cell

insulin is a kind of _______ hormone released by the __________. Describe what it does.

peptide (water-soluble), pancreas

released in response to high glucose concentration in the blood, it activates the expression of GLUT4

GLUT4

activated by insulin, it’s a glucose transporter that brings glucose into cells

estradiol is a kind of ______ hormone produced primarily by the _________. It’s the ________ estrogen.

steroid (lipid-soluble), ovaries, primary

identify A and B

A: Hypothalamus

B: Pituitary Gland

function of the hypothalamus (regarding hormones)

secretes releasing + inhibiting hormones, which act on the anterior pituitary

☆ also produces ADH and Oxytocin, which are stored in the posterior pituitary and released upon appropriate hypothalamic stimulation

Releasing and Inhibiting Hormones

hormones whose main purpose is to control the release of other hormones, either by stimulating or inhibiting their release.

The pituitary is divided into two lobes:

Anterior (master gland) and Posterior

Anterior Pituitary Gland function

mostly releases tropic hormones — hormones that control another gland elsewhere in the body

Hormones released by the Anterior Pituitary Gland

• Prolactin (PRL)

• Growth Hormone (GH)

• Thyroid-stimulating Hormone (TSH)

• Adrenocorticotropic Hormone (ACTH)

• Follicle-stimulating Hormone (FSH)

• Luteinizing Hormone (LH)

🎯 target tissues of the hormones released by the anterior pituitary gland

• PRL → mammary glands

• GH → bone and soft tissue

• TSH → thyroid glands

• ACTH → adrenal cortex

• FSH & LH → ovaries and testes

Posterior Pituitary Gland function

stores ADH and oxytocin, both of which were produced in the hypothalamus

ADH role

🎯 in the kidneys

• expresses aquaporins in collecting duct of nephron (allows for water reabsorption)

Oxytocin role

🎯 uterus, mammary glands

• promotes uterine contractions (positive feedback)

• stimulates milk release

Name 3 thyroid hormones

• Calcitonin (targets bones)

• Thyroxine and Triiodothyronine (target most cells)

What do the thydroid hormones do?

• Calcitonin: ↓ [Ca2+] in the blood

• Thyroxine and Triiodothyronine: ↑ metabolic rate — essential for normal body growth!

Parathyroid Hormone (PTH)

produced by the parathyroid (duh!): it ↑ [Ca2+] in blood and stimulates vitamin D activation

🎯 bones, kidneys, intestines

why is vitamin D important?

it allows the body to absorb calcium, vital in maintaining/building bones and teeth

_____ deficiency occurs because our bodies don’t make the mineral naturally — this deficiency hurts ________ function, which results in:

IODINE, thryoid function, slow metabolism

The adrenal glands are composed of:

Adrenal Cortex and Adrenal Medulla

name two hormones produced by the adrenal medulla

• epinephrine

• norepinephrine

🎯 both target receptor sites throughout the body in response to stress

name two hormones produced by the adrenal cortex

• aldosterone (targets kidney tubules, deals w salt-water balance)

• cortisol (targets most body cells)

Prolactin vs Oxytocin effect on mammary glands

prolactin causes milk to be produced, oxytocin causes milk to be released

FSH and LH are what kind of hormone? What do they do?

they are peptide hormones, and they are gonadotropins (act on reproductive glands)

⇨ produce gametes, as well as other hormones

Label the pituitary gland.

A: ANTERIOR pituitary

B: POSTERIOR pituitary

label the glands

A: Pineal Gland

B: Hypothalamus

C: Pituitary Gland

D: Thyroid Gland

E: Parathyroid Gland

F: Mammary Glands

G: Pancreas

H: Adrenal Gland

I: Ovaries/Testes