Chapter 16: endocrine system

Endocrine system

• network of glands

• chemical message

• carried by blood

• slow acting

• throughout the body

• long term affects

6 Major glands

• pituitary

• thyroid

• parathyroid

• adrenal

• pineal

• thymus

autocrines (Not a hormone)

chemical made by the cell and works on the cell that made it

paracrine (not a hormone)

work on a nearby cell

endocrines

works on a cell that is far away

2 ways to classify a hormone

1. amino acid/protein

2. Steroids/fat/ lipids

amino acid based hormones

act at the cells surface through 2nd messengers at the plasma membrane

steroid based hormones

work inside of the cell in the intracellular environment of the cell (direct gene activation)

hormone half life

how long something survives in the body (steroids: long and amino acids: short)

target cell specificity

what the hormone needs to bind in order to affect the cell, must have a specific receptor

when a hormone hits the receptor what can it do?

• electrolyte to shift

• protein synthesis

• induce secretory activity

• on or off switch

hormones

alter target cell

how do hormones alter the target cell?

• second messenger (amino acids)

• direct gene activation (steroid)

3 triggers for a gland to release a hormone

• Humoral stimuli

• Neural stimuli

• Hormonal stimuli

humoral stimuli

secretion of hormones in direct response to changing blood levels of the specific hormone

neural stimuli

• nerve triggers release of hormone

• have release of a hormone in response to action potential

• ex: adrenal

hormonal stimuli

 release of hormones in response to another hormone

tropic

humoral stimulus - cause the release of a hormone from another gland

pituitary gland

• two lobed

• secretes nine major hormones

• connected to hypothalamus via a stalk

posterior lobe (neural tissue)

receives, stores, releases hormones from the hypothalamus

oxytocin

reproductive hormone, labor and birth, triggers milk production

ADH (antidiuretic hormone)

prevents urine formation in the body, regulates blood pressure and water

diuretic

any drug or chemical that causes the body to create urine

vasoconstriction

closes the artery which raises blood pressure and water

Anterior lobe (glandular tissue)

synthesizes and secretes a number of hormones, works through hormonal stimuli - releases and inhibits

6 anterior lobe hormones

• Growth hormone

• Thyroid stimulating hormone

• follicle stimulating hormone

• luteinizing hormone

• prolactin hormone

Indirect action (GH)

works through insulin like growth factors

Growth hormone description

Growth hormone releasing hormone from pituitary, anabolic effects on growth metabolism

direct action (GH)

promote metabolic fuel (catabolic), fat and sugar breakdown - energy

hypo and hypersecretion of GH

affects growth in the body (Shorter or taller)

Thyroid stimulating hormone

• Get Thyroid releasing hormone from hypothalamus and releases thyroid stimulating hormone from the pituitary gland

• t3/t4 = thyroid

• makes Thyroid and calcitonin

adrenocorticotropic hormone

stimulates the adrenal cortex to release corticosteroid from the cortex and makes stress hormones

Gonadotropins

1. Triggered by GnRH from hypo

2. Regulates the function of egg and gamete production

3. FSH stimulates reproductive production

4. LH stimulates the production of estrogen and testosterone (also stimulates ovulation)

what controls the adrenal cortex

anterior pituitary

prolactin

stimulates milk production

what does the thyroid gland make

thyroid and calcitonin

what does the thyroid hormone regulate?

energy use

what does calcitonin do?

lowers blood calcium - stimulates osteoblasts

what does parathyroid gland do

raises blood calcium - inhibits osteoclast

what corticosteroid is in the adrenal cortex outer layer

aldosterone

mineralcorticoids (aldosterone)

sodium balancing hormone

what does the RAA pathway do

elevated BP and works through sodium

what does cortisol do?

anti-inflammatory, increases glucose levels in the blood - stress

Epinephrine

prepares body for fight or flight response

what does the adrenal medulla produce

catecholamines

pancreas

produces insulin and glucagon

what does glucagon do?

raises blood sugar (liver)

what does insulin do?

lowers blood sugar

Gonads

regulates menstrual cycles and sperm production

pineal gland

brain, makes melatonin

thymus

makes T cells (immune system)

ANP hormone

Heart, lowers blood pressure, produces atrial natriuretic peptides

Type 2 diabetes

insulin resistant, body secretes enough but the receptors are blocked

type 1 diabetes

does not produce enough insulin

what is blood and circulation composed of?

Plasma and cells

functions of blood

transports, regulates, and protects

Hematocrit normal percentage

45%

Anemic hematocrit percentage

25%

Buffy coat healthy percentage

1% or less

Plasma healthy percentage

55% - liquid portion with out cells

what is the main component of plasma

90% water, rich in protein