Week 6 Study Guides

Endocrine glands

Ductless organs or groups of cells that secrete hormones directly into the blood or other body fluids.

A single gland can

secrete multiple hormones

Hormones are

chemicals released into the bloodstream by endocrine glands

Secreted hormones enter through

the Interstitial fluid and diffuse in the blood

Exocrine glands

secrete products into ducts that lead to the body surface or internal lumen

Hypothalamus secrets

several neurohormones that stimulate or inhibit anterior pituitary gland function

Hypothalamus synthesizes

ADH and Oxytocin

ADH and Oxytocin are stored in

posterior pituitary

Heart makes

Atrial natriuretic peptide (ANP) → lowers BP

ANP lowers

blood Sodium which lowers BP

Adrenal glands make

E/NE

Cortex makes

Aldosterone

Aldosterone

Hormone that stimulates the kidney to retain sodium ions and water

Aldosterone regulates

extracellular sodium and potassium ion levels

Aldosterone makes

Cortisol

Liver produces

IGF-1

IGF-1 controls

growth of bone, secretion angiotensinogen

Angiotensinogen

a plasma protein produced by the liver, precursor for angiotensin II

Kidneys secrete

erythropoietin and renin

Kidney produces

1.25 dihydroxyvitamin D

1.25 dihydroxyvitamin D

stimulate the intestinal absorbtion of calcium thus the major event in vitamin D deficiency is decreased intestinal calcium absorption, resulting in decreased plasma calcium.

Renin function

converts angiotensinogen to angiotensin II

Pancreas makes

Insulin and Glucagon

Insulin function

decreases blood glucose levels

Glucagon function

increases blood glucose levels

Blood vessel hormones

cells of many blood vessel walls express enzymes that are required to complete the synthesis of Angiotensin II, to maintain normal blood pressure

Adipose Tissue produces

leptin, resistin, adiponectin

Adipose hormones function

regulate appetite and metabolic rate

Anterior Pituitary function

Produces hormones with diverse actions related to metabolism, growth and others

Anterior pituitary hormones

GH, TSH, ACTH, FSH, LH, PRL

Posterior pituitary function

secretes ADH and oxytocin (contraction of uterus and milk ejection in lactating women; affect sperm motility)

ADH is also known as

Vasopressin

Vasopressin function

increases water reabsorption in the kidney and affects learning and memory

Pineal gland makes

melatonin in response to sunlight

Parathyroid gland makes

parathyroid hormone (PTH)

PTH function

increases blood calcium levels

PTH stimulates

production of vitamin D in the kidneys

Thyroid makes

T3, T4, calcitonin

Thyroid hormones

hormones produced by the thyroid gland primarily responsible for regulation of metabolism

Calcitonin function

Lowers blood calcium levels

Stomach and small intestine hormones

gastrin, cholecystokinin, secretin

Gastrin, cholecystokinin, and secretin functions

regulate pancreatic activity, facilitate digestion and control appetite

Ovaries produce

estrogen and progesterone

Testes produce

androgens like testosterone

Hormones function

Control, integration and coordination of cell activities and organ function

Which is faster: hormones or the nervous system

Nervous system

Give an example of an endocrine gland and an exocrine gland and explain the major anatomical feature that distinguishes them.

Endocrine gland: Heart

Exocrine gland: Sweat gland

What organ contains both endocrine and exocrine glands?

Pancreas

Hormone are divided into 3 structural classes

1. peptides and proteins

2. steroids

3. amines

Amines are derivatives of

Tyrosine

Amine hormones

• Thyroid Hormones

• Catecholamines(epinephrine, norepinephrine)

• Dopamine (hypothalamus)

Dopamine is produced in the

Hypothalamus

Peptides and proteins are

short and long chains of amino acids

Examples of peptides and proteins

insulin, glucagon, oxytocin

Steroids are produced in

Adrenal cortex, Testes and Ovaries

Steroids are made from

Cholesterol

Where are steroid stored

not in the cholesterol

Steroid can easily diffuse across

palasma membrane to bind to plasma proteins

Amine hormones

amino acid derivatives

Iodine containing hormones

Thyroid hormones

Catecholamines secreted by

Adrenal medulla and Hypothalamus

Peptides and proteins are typically synthesized as

larger (inactive) molecules

Peptides and proteins are cleaved into active fragment by

post-translational modification

Post-translational modification

changes made to polypeptides following translation

Are peptides free in the plasma membrane

yes

Signaling mechanisms for peptides and proteins include

cAMP, enzyme activation by receptor, intrinsic enzymatic activity

Rate of excretion for peptides

high/fast

Steroid hormones bind to

protein receptors in the cytoplasm or nucleus of the target cell

Signaling mechanism for steroid hormones

Steroids: nuclear receptors

Rate of excretion for steroid Hormones

slow

Adrenal cortex produces

aldosterone, cortisol, androgens, DHEA and androstenedione

Peptide hormones and catecholamines

soluble in plasma

Steroid and thyroid hormones

Poorly soluble

Mostly bound to plasma proteins

Small concentrations dissolved in plasma ("free hormones")

Only free hormones interact with target cells

Insulin is a

peptide hormone

Cortisol is a

steroid hormone

Thyroid hormone is a

amine hormone

Which classes of hormones are carried in the blood mainly as unbound, dissolved hormones?

Peptides and Catecholamines circulate primarily dissolved in plasma

Hormones mainly bound to plasma proteins?

Steroid and thyroid hormones

Why is there a difference in hormones

The main reasons for the difference is the solubility of the different classes of hormones in plasma and a way to decrease the metabolism of the hormone

Liver and kidneys are responsible for

excreting and getting rid of hormones

Secreted hormones in the blood are excreted by

B/B movements, inactivated by metabolism or activated by metabolism

Activated hormones from metabolism bind to

receptors on target cell and produce a response

The liver and kidneys remove hormones from the plasma by

metabolizing or excreting them

Peptide hormones and catecholamines are removed

rapidly

Steroid and thyroid hormones are removed

slowly due to binding with plasma proteins

Some hormones are metabolized to

active molecules in target cells and other organs

Receptors bind to

hormones and exert an action

Steroids and thyroid hormone receptors location

Intracellular cytoplasm or nucleus

Peptide hormones and catecholamines receptors location

on plasma membrane

Up-regulation

target cells form more receptors in response to the low concentration of hormone

Down regulation

target cells lose receptors in response to the hormone

Permissiveness

when another hormone is needed for a hormones to exert its full affect

Thyroid hormone permits

epinephrine to release fatty acids

Thyroid hormone by itself

Little to no fatty acid release

Epinephrine by itself

Small amounts of fatty acid released

Epinephrine+thyroid together

large amounts of fatty acid released

Peptide and Catecholamine activated receptors influence

• Enzyme activity that is part of the receptor

• Activity of JAK associated with receptor

• G-proteins that are coupled to ion channels and activate secondary messengers

• Can be rapid (enzyme) or have delayed effects (transcription)

Steroid and thyroid Hormone influence

activation or inhibition of transcription of certain genes

Steroid and thyroid action is

slow

Peptide and catecholamine action is

fast