Chapter 11 : Endocrine System

Endocrine System: What is it?

system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body

Hormones affect other endocrine glands or body systems

ES and Homeostasis Homeostasis

STIMULUS

HypothalamusReleasing Hormone

(Release-Inhibiting Hormone)

PituitaryStimulating Hormone

GlandHormone

Target

Basic Structure of Feedback Loop

Environmental Stimulus Stimulates Control Center (Brain-hypothal.) Hypothalamic hormones stim. Pituitary Pituitary hormone stim. Target area Target area produces change Change acts negatively or positively on the cycle.

A. Positive Feedback

Not common Classic example:

Action of OXYTOCIN on uterine muscle during birth.

Positive Feedback

Baby pushes on cervix Nervous signal to Hypothalamus Hypothal. manufactures OXY OXY transported to POSTERIOR

PITUITARY & released OXY stimulates uterine contraction Loop stops when baby leaves birth canal

Negative Feedback: Thyroid

IV. Specific Endocrine Events

A. Thyroid Hormone

B. Growth Hormone

C. Adrenal Cortex Hormones

D. Sex Steroids

Endocrine System: Team Players

The Pituitary Gland Thyroid Gland Parathyroid Glands Adrenal Glands Pancreas Thymus Pineal Gland Gonads

Pituitary/ Hypophysis

Anterior Secretions:– TSH– ACTH– FSH– LH– ISCH– LTH– GH/ STH– MSH

Pituitary gland: a small gland located on a stalk hanging from the base of the brain

“The Master Gland”

– Primary function is to control other glands.

– Produces many hormones.

– Secretion is controlled by the hypothalamus in the base of the brain.

Posterior Secretions:– ADH– Oxytocin

Thyroid Gland

Secretions:– T3: metabolism regulation– T4: metabolism regulation– Calcitonin: promotes

absorption of calcium from blood and bones

Thyroid Gland: butterfly shaped, left and right halves fused by an isthumus. On either side of the larynx

“The Weight Gland”

– Controls metabolism, iodine uptake, blood calcium levels

Adrenal Glands

Cortex Secretions (Steriods):

– Mineralocorticoids

– Glucocorticoids

– Androgens

Adrenal Glands: Located cranial to the kidney. Each gland has 2 parts: cortex and medulla

“The Reaction Gland”

– Regulates electrolytes, metabolism, sexual functions, injury response

Medulla Secretions:

– Epinephrine– Noreeprinep-

hrine

Pancreas

Endocrine Secretions:

– Insulin– Glucagon

Pancreas: aggregation of cells located near the proximal duodenum

“The Sugar Regulation Gland”

– (Endocrine FXN) secretion of blood-glucose regulation

Gonads: gamete production

Testes– Testosterone

2ndary sex characteristics

Ovary Secretions: Stimulated by hCG which is secreted by placenta

– Estrogen 2ndary sex

characteristics

– Progesterone Maintains preg

Common Procedures

Assays: tests amount of hormone present Thyroid Stimulation Test: blood analysis of

thyroid levels ACTH Stimulation Test: blood analysis of

cortisol levels in the blood

Common Ailments

Acromegaly: enlargement of extremities due to over active growth

Cushing’s Disease/ Hyperandrenocorticism: excessive adrenal cortex production resulting in increased urination, drinking, and distribution of body fat

Diabetes Mellitus: metabolic disorder, of inadequate secretion of insulin

Activities

For Each Endocrine player– List the secretions and what each secretion performs

in the body Define an Endocrine Disease include

– Symptoms, Prevention, Treatment, and Definition Outline a Positive and Negative Feedback

reaction in the body (can use the pregnancy example, but not the Thyroid example)– Design a Flow chart for the reactions you described