INTEGRATIVE PHYSIOLOGY EXAM 3: ENDOCRINOLOGY

Hormones

Chemical messengers that travel int he blood to alter target cells’ functions to maintain homeostasis with receptors to bind with, made in glands or cells, etc.

Phermones

Organism to organism response

Stimulus => gland => Hormone => action

What is the signaling pathway for a hormone?

Preprohormone

A large and inactive hormone

Prohormone

Post-translation modification

Peptide Hormone

Receptor complex-signal transduction system

1) mRNA on ribosomes bind amino acid to peptide chains (prohormones)

2) Enzymes in ER chop off signal sequence to make an inactive prohormone

3) Prohormone passes from ER to Golgi

4) Secretory vesicles containing enzymes/prohormones bud off Golgi

5) Prohormones are chopped off into one or more active peptides (some fragments)

6) Releases contents through exocytosis (into circulation)

Steps that peptide hormones can get synthesized and packaged?

hormones + other peptides + signal sequences (6 TRH with 3 AA each)

What can preprohormones break up into

active hormones (ACTH + Lipotropin + endorphin) + Fragment

What can prohormones break up into

insulin + c-peptide

What can proinsulins break up into

cortisol , estrogen, & testosterone

Types of steroid derived hormones?

Meant to activate DNA for protein synthesis with a slower acting & longer half-life and are typically lipophilic in which they can enter the cell that is mostly cytoplasmic or nuclear receptors.

What are steroid derived compounds used for?

1) Hydrophobic steroids bound to plasma protein carriers in the blood , those that aren't can diffuse into the target cell (those that are bound to a plasma protein cannot cross the membrane)

2) steroid hormone receptors can b located in the cytoplasm or nucleus ( in the membrane as well if they so choose to , which can cause a cascade of responses)

3) Receptor - Hormone complex can bind to DNA to activate or repress one or mor genes (activated genes create new mRNA to more back in cytoplasm

What is the action of steroid hormones?

Tyrosine & Tryptophan

Types of amine derived hormones?

Acts as a negative feedback response

What are amine derived compounds used for?

↑ blood glucose —> Pancreas —-> insulin —-> target tissues —->glucose uptake/utilization —> ↓ Blood glucose

How does insulin release work?

posterior Pituitary

Neuropeptide hormone in bloodstream acts as chemical messenger

Hypothalamus

Has axons that extends down to the posterior pituitary's blood stream or closer to blood vessels and releasing hormones closer in the anterior pituitary

Anterior Pitutiary

releasing hormones will stimulate anterior pitutary to release own hormone (different foreach

oxytocin

think about the reproductive system = cervix tends to prevent the baby from coming out, the head will grow and stretch the cervix

Baby wants to push out due to head being too big

Stimulus for oxytocin?

send to posterior pitutary in hypothalamus

Sensory neurons in oxytocin?

stimulus triggers neurons to release an action potential

Posterior Pitutary hypothalamus in oxytocin?

oxytocin release

stimulus smooth muscles of uterus to release baby or Mammary glands where oxytocin can stimulate milk injection

Oxytocin and ADH/vasopression

Posterior pitutiary glands?

Vasopnession/antidiuretic (ADH)

responds to the high osmolarity of the bloodstream by acting on the kidneys toreabsorb more water (what leaves/what stays?) so the fluid can be diluted in the blood stream (same process as oxytocin except on kidneys

Thyroid Stimulating Hormone (TSH), Adernacorticotropic Hormone (ACTH), Growth Hormones, Prolactin, Gonadotropin(s)(

What are examples of anterior pituitary glands?

Thyroid Stimulating Hormone (TSH)

Tropin hormone that tells thyroid to make its own hormone

TSH stimulates thyroid to produce own hormones

Stimulus to TSH?

T₃/T₄ produced

Released during TSH in the Anterior Pituitary?

Tells variety ol cells to do chemical reactions/metabolism

What is the reaction to TSH after T₃ and T₄ are produced?

The adrenal cortex to release a hormone due to perceived stress

What does ACTH stimulate?

cortisol (stress hormone that releases fight or flight/stress)

What does the ACTH system release/produce?

Growth Hormones

released during puberty and with bones

Prolactin

In response to hypothalamus when women are pregnant/postpartum to feed baby milk (milk production in mammary glands/differentiate tissues wi myoepithelial tissue development could contract to eject milk)

Gonadotropin(s)

Follicle Stimulating Hormone / Lutenizing Hormones will trigger hormone release in different tissues such as sex organs/testes & ovaries) => released during puberty

testes?

(Males) what does the FSH act on

stimulates mature sertoli cells

(Males) What does the FSH stimulate?

guide sperm to maturation

(Males) What does the FSH response is in the end?

testes?

(Males) what does the LH act on

stimulates testes to produce hormone testosterone

(Males) What does the LH stimulate?

triggers sperm differentration 2^o sex characteristics

(Males) What does the LH response is in the end?

ovaries

(Females) what does the FSH act on

produce estrogen/progesterone

(females) What does the FSH stimulate?

Estrogen builds on secondary characteristics and have progesterone/estrogen helped uterine lining to prepare baby

(Females) What does the FSH response is in the end?

stimulates ovulation in ovaries

(females) What does the LH stimulate?

Thyroid

The organ can release T₃/T₄ , but also release calcitonin /released in response to high blood calcium

Calcitonin

stimulates osteoblasts / bone builder cells to deposit calcium in the bone so blood calcium can go back to homeostasis

– Decreases bone resorption

– Increases renal calcium excretion

Parathyroid Glands

This releases parathyroid hormone to act on osteoclasts to break down bone and release ca²⁺ back to normal

Parathyroid Hormone

act on osteoclasts to break down bone and release ca²⁺ back to normal

– Mobilizes calcium from bone

– Enhances renal reabsorption of calcium

– Stimulates release of Calcitriol

• Calcitriol increases intestinal calcium absorption

Adernal Gland/cortex

Releases Aldosterone when the RAAS system is activated when there is low BP

Low Blood Pressure

Stimulus for Adrenal Gland/Cortex

RAAS system activated

What is activated in the Adrenal Gland/Cortex

released aldosterone-

Hormone released in Adrenal Gland?

Aldosterone

kidneys to reabsorb salt (unintentionally increases water so blood volume and pressure goes up

Adrenal Medulla

when sympathetic nervous system stimulated in response to stress , it fines and goes down through this gland → release a neurotransmitter known as norepinephrine signals the hormone epinephrine (adernaline) = speeds up heart and works on contraction strength (can circulate properly) and help bronchodilate

norepinephrine

Neurotransmitter that signals the hormone epinephrine

Epinepherine

speeds up heart and works on contraction strength (can circulate properly) and help bronchodilate

stress stimulus

Stimulus for Adrenal Medulla?

sympathetic system stimulated

What is stimulated in Adrenal Medulla?

releases norepinephrine neurotransmitter

Neurotransmitter released in Adrenal Medulla?

release hormone epinephrine

Hormone released in Adrenal Medulla?

speeds up heart rate

Release signal in Adrenal Medulla?

Kidneys (as a gland)

When there is low filtration pressure (means blood pressure) = needs certain filters to pump out properly (low filtration = more toxins can go through)

Renin

will spark a variety ol processes to release blood pressure Low blood O₂ stimulus

Low filtration

Stimulus in Kidneys?

Renin

What is the hormone released in the kidneys?

stimulates to release EPO

What else is stimulated in the kidneys

Redbone marrow to stimulate red blood cells to release erthocytes

Release signal for kidneys?

Beta cells

act and stimulates insulin that can act on some liner, muscle tissue , adipocytes → use transporters to allow glucose to travel in the cell to lower blood sugar

Alpha cells

act and stimulates glucagon when there is low glucose = trigger to release stored glucose (glycogen) and cuts the chains ol glycogen torelease glucose

Pineal gland

Melatonin produced to help with the sleep wake cycle

Melatonin

produced to help wl the sleep wake cycle

Absence of light stimulus

Stimulus for Pineal Gland

Melatonin

Hormone stimulated in the Pineal gland

tells body to sleep.

What is the release signal in the pineal gland?

1) Neurons synthesizing trophic hormones release them into capillaries of the portal system

2) Portal vessels carry trophic hormones directly to anterior pituitary

3) Endocrine cells release their hormones into the second set of capillaries for distribution to the rest of the body

Hypothalamic Hypophyseal Portal System Steps

1) Messenger RNA on ribosomes binds amino acids into a peptide chain known as preprohormone, which is directed into the ER lumen b y a signal sequence of amino acids

2) Enzymes in the ER chop off the signal sequence to create an inactive prohormone

3) Prohormone passes from the ER through the Golgi complex

4) Secretory vesicles containing enzymes and prohormone bud off the Golgi. The enzymes chop the prohormone into one or more active peptides plus additional peptide fragments

5) Secretory vesicle releases contents by exocytosis into the extracellular space

6) Hormone moves into circulation for transport to its target.

Peptide Hormone Synthesis, Packaging, and Release

a hormone, other peptides and signal sequence

What does a preprohormone compose of?

Active hormones and other peptide fragments

What does a prohormone compose of?

Insulin and a C-peptide

What does a proinsulin compose of?

1. Surface receptor

2. Hormone binds to surface receptor

3. Enzyme activation

4. Open channels

5. Second messenger systems

6. Cellular response

Peptide Hormone-Receptor Complex

Steroid Hormones

Cholesterol-derived

• Lipophilic and can enter target cell

• Cytoplasmic or nuclear receptors (mostly)

• Activate DNA for protein synthesis

• Slower acting, longer half-life

Examples

• Cortisol, estrogen, and testosterone

Amine Hormones

Derived from one or two amino acids

Catecholamines

– Epinephrine

– Norepinephrine

– Dopamine

Amine Hormones: Examples

1) Hormone is made and packaged in cell body of neuron

2) Vesicles are transportered down the cell

3) Vesicles containing hormone are stored in posterior pituitary

4) Hormones are released in the blood

Posterior Pituitary Gland Steps

Somatotrophs

Secrete growth hormone (GH)

Thyrotrophs

Secrete thyroid stimulating hormone (TSH)

Corticotrophs

Secrete adrenocorticotropic hormone (ACTH)

Lactotrophs

Secrete prolactin (PRL)

Gonadotrophs

Secrete two gonadotropins:

o Follicle-stimulating-hormone (FSH)

o Luteinizing hormone (LH)

Hypothalamus

Release of hormones by the anterior pituitary is regulated by what?

• Growth hormone–releasing hormone (GHRH),

• Thyrotropin-releasing hormone (TRH).

• Corticotropin-releasing hormone (CRH)

• Prolactin-releasing hormone (PRH)

Gonadotropin-releasing hormone (GnRH)

What are examples of Releasing hormones f

• Growth hormone–inhibiting hormone (GHIH)

• Prolactin-inhibiting hormone (PIH)

What are examples of inhibiting hormones?

Hypothalamic stimulation

from CNS

Pituitary stimulation

from hypothalamic trophic hormones

Endocrine gland stimulation

from pituitary trophic hormones

Permissive

Two hormones that work through it together

Synergistic

More than one or two hormones that work through it together

Antagonistic

When two hormones work aganist each other