Ahs 132 Week 7 Endocrine

Front 1

Hypothalamus

Back 1

Hypothalamic neurons produce ADH and oxytocin
Transports these hormones along axons (nerves) within the infundibulum and releases them into the circulation at the neurohypophysis (posterior pituitary)

Front 2

Mechanisms of Intercellular Communication

Back 2

Direct communication - gap junctions
Paracrine communication - through extracellular fluid
Endocrine communication - through circulatory system
Synaptic communication - across synaptic clefts

Front 3

Classes of Hormones

Back 3

Amino acid derivatives
Peptide hormones
Lipid derivatives

Front 4

Classes of Hormones

Amino Acid Derivatives

Back 4

Hormones synthesized from the amino acids tyrosine and tryptophan
Tyrosine derivatives - thyroid hormones (T3, T4), epinephrine, norepinephrine, and dopamine
Tryptophan derivative is melatonin

Front 5

Classes of Hormones

Peptide Hormones

Back 5

Peptide hormones are chains of amino acids
Usually synthesized as inactive hormones that become activated
2 groups -
glycoproteins
short polypeptide chains to proteins
This group includes all the hormones secreted by the hypothalamus, heart, thymus, digestive tract, pancreas, and neurohypophysis, as well as most of the hormones secreted by the adenohypophysis

Front 6

Classes of Hormones

Peptide Hormones - Glycoproteins

Back 6

TSH - thyroid stimulating hormone
LH
FSH
Epo

Front 7

Classes of Hormones

Peptide Hormones - other group

Back 7

ADH
Oxytocin
GH - Growth hormone
PRL - prolactin
Insulin
PTH

Front 8

Classes of Hormones

Lipid Derivatives

Back 8

Eicosanoids
Leukotrienes
Steroid hormones

Front 9

Classes of Hormones

Lipid Derivatives - Steroid Hormones

Back 9

Comes from cholesterol
Released by female and male reproductive organs( androgens, estrogen and progesterone), the adrenal cortex (corticosteroids), and the kidneys (calcitriol)

Front 10

Dopamine

Back 10

Can't cross blood-brain barrier
Alpha dopa can cross the barrier

Front 11

Mechanisms of Hormone Action

Back 11

Hormone must interact with a specific receptor
Receptor is a protein molecule
Receptors are located either on the plasma membrane of a cell or inside the cell

Front 12

Hormones

Plasma Membrane Receptors

Back 12

First and second messengers

Front 13

Hormones

Plasma Membrane Receptors
First and second messengers

Back 13

Hormone that acts on a plasma membrane doesn't have a direct effect on activities inside the cell
Hormone is the first messenger
Uses an intermediary, or second messenger that acts as an enzyme or inhibitor
Most important second messengers are cAMP (cyclic AMP), cGMP (cyclic GMP, and calcium ions
Link between first and second messenger usually involves a G protein

Front 14

G Protein and cAMP

Back 14

Link between first and second messenger
It is an enzyme complex coupled to a membrane receptor
Name comes from the fact that these proteins bind to GTP
G protein is activated when a hormone binds to its receptor on the plasma membrane
Many G proteins exert their effects by changing the concentration of the second messenger cAMP; a cytoplasmic enzyme PDE (phosphodiesterase) inactivates cAMP

Front 15

G Protein and Calcium ions

Back 15

see pg. 610

Front 16

G Protein and cAMP

Back 16

see pg. 610

Front 17

Hormones

Intracellular Receptors

Back 17

Steroid hormones diffuse across the lipid part of the plasma membrane and binds to receptors in the cytolasm or nucleus
Thyroid hormones - cross the plasma membrane by a transport mechanism

Front 18

Hormones

Intracellular Receptors - Thyroid Hormones

Back 18

TH cross the plasma membrane by a transport mechanism
In the cytoplasm, the hormones bind to receptors within the nucleus and on mitochondria
The hormone-receptor complexes in the nucleus activate specific genes or change the rate of transcription
Increases the mitochondrial rates of ATP production

Front 19

Calcitonin

Back 19

Decreases blood calcium levels

Front 20

Proteins

Back 20

Can act as
enzymes
transporters
receptors

Front 21

Hormone receptors

Back 21

Very specific
Lignads bind to receptors

Front 22

Hypothalamo-Pituitary Portal Circulatory System

Back 22

Hypohyseal portal system
Hypothalamus secretes regulatory hormones that control the production of hormones in the anterior pituitary
Unusual vascular system - capillary networks are linked by portal vessles rather than arteries and veins

Front 23

Oxytocin

Back 23

Posterior pituitary
Increases uterine contractions

Front 24

ADH

Back 24

Anti-diuretic hormone
Vasopressin
Causes water retention
Secreted in response increased osmolarity of the blood, drop in blood pressure
In high concentration causes vasoconstriction
Thirst center - controls drinking
Works through the kidneys and water retention or sweating

Front 25

ADH

Back 25

If you are overhydrated, ADH will decrease
If dehydrated, ADH will increase and cause the kidney to retain water

Front 26

Diabetes Insipidus

Back 26

Develops because the posterior pituitary doesn't secrete enough ADH
As a result, there's too much water loss through excess urination
As a result you are constantly thristy

Front 27

Thyroid Hormone

Back 27

T3 - triiodothyroxine
T4 - tetraiodothyroxine
Regulates basal metabolism, growth, nervous system, development, and maturation

Front 28

Thyroid Hormone

Back 28

Works through genes and mitochondria - ATP usage

Front 29

Hypothryoidism

Back 29

Low thyroid hormone levels
If occurs during pregnancy, the baby is born with cretinism - mental retardation

Front 30

Thyroid

Parafollicular cells

Back 30

C cells
Secrete calcitonin
Causes decrease in calcium levels by putting it into the bone