Chapter 12 The Endocrine System

Terminology and information on the glands and organs that release hormones into blood and bodily fluids.

adreno

adreno glands

calci

calcium

cortico

outermost

-down

reduction

glyc

sugar

-ism

cause

kal

potassium

natr

sodium

para-

near

-plasia

growth

-son/-sone

steroid

syn

together

thyr

thyroid

tropic/trophic

influencing the acitivty of a gland

up-

increase

Endocrine system consists of…

glands that secrete hormones into the blood or body fluids (like interstitial fluid)

interstitial fluid

AKA tissue fluid. Fluid surrounding tissues.

Hormones

Bind to specific receptors on target cells

target cells

contain specific receptor for a hormone

The major endocrine glands

• Pituitary gland

• Thyroid gland

• Parathyroid glands

• Adrenal glands

• Pancreas

• Gonads

  • Testes and ovaries

Minor endocrine glands

Other organs that contain hormone secreting tissues in cells that are not in the endocrine system

Pituitary gland

• AKA hypophysis

• Located under hypothalamus, attached to pituitary stalk (infundibulum)

• Has two parts

  • Anterior pituitary

  • Posterior pituitary

Anterior pituitary

Receives signals from hormones released by hypothalamus

Posterior pituitary

Directly connected by neurons of hypothalamus

Adrenocorticotropic Hormone (ACTH)

• Anterior pituitary gland hormone

• Signals adrenal cortex to release hormones

• Stimulates release of corticosteroids

Thyroid Stimulating Hormone (TSH)

• Anterior pituitary gland hormone

• Stimulates thyroid to release hormones

Prolactin (PRL)

• Anterior pituitary gland hormone

• Stimulates the mammary glands to produce milk

Follicle Stimulating Hormone (FSH)

• Anterior pituitary gland hormone

• Egg maturation/Sperm production

Luteinizing Hormone (LH)

• Anterior pituitary gland hormone

• Triggers release of egg from ovary

• Testosterone production

Growth hormone (GH)

• Anterior pituitary gland hormone

• Stimulates body cells to grow and multiply

Antidiuretic Hormone (ADH) (also called vasopressin)

• Posterior Pituitary Gland Hormones

• Directs kidneys to reabsorb water

Oxytocin (OT)

• Posterior Pituitary Gland Hormones

• Stimulates uterine contractions during labor

• Milk ejection

• Stimulates smooth muscles of reproductive tract

What are neurohormones (Define and example)

ADH and Oxytocin. The posterior pituitary does not actually make these hormones. Instead the neurons of the hypothalamus make them

What are the main hormone producing cells of the thyroid

• Follicular Cells

• Parafollicular (extra follicular cells)

Location of Thyroid Gland

Wrapped around anterior trachea

The follicular cells produce…

Thyroid Hormones

The two types of Thyroid Hormones

• T4 (Thyroxine)

• T3 (Triiodothyronine)

The parafollicular cells produce the hormone…

Calcitonin (CT)

Function of Thyroid Hormones

Regulates metabolism of body cells

Calcitonin (CT)

• Produced by Thyroid gland

Released when blood calcium levels are too high. Prevents release of calcium from bone. And calcium is released in urine

Hypercalcemia

High calcium levels

T4 is the ___ of a hormone

inactive form

T3 is the ___ of a hormone

active form of a hormone

What is needed to make T3 and T4

Iodine

Parathyroid Glands

Four small glands located on posterior side of thyroid gland lobes. Chief cells of glands produce parathyroid hormone (PTH)

Function of Parathyroid Hormone

• Produced by parathyroid glands

Released when blood calcium is too low. Signals bone to release calcium and for the intestine to absorb calcium. Prevents calcium being in urine

Adrenal Glands

Sit atop each kidney.

Divided into two parts

• Adrenal cortex

  • Cortex means outer layer

• Adrenal medulla

  • Medulla means inner layer

The adrenal cortex produces ___

three major categories of steroid hormones collectively called corticosteroids

What are the two hormones the adrenal medulla secretes

Epinephrine (EPI)

Norepinephrine (NE)

Glucocorticoids/Cortisol purpose

• Produced by adrenal cortex

Helps body manages stress

Mineralocorticoids / Aldosterone (ALD)

• Produced by adrenal cortex

Prompts kidneys to retain sodium and excrete potassium

Androgens/Weak sex hormones

• Produced by adrenal cortex

Plays a role in sexual development

Epinephrine (EPI or adrenaline)

• Produced by adrenal medulla

Released as part of sympathetic nervous system aka fight or flight

Norepinephrine (NE or noradrenaline)

• Produced by adrenal medulla

Released as part of sympathetic nervous system aka fight or flight

Pancreas (Endocrine function)

Releases insulin and glucagon

Pancreatic cells that secrete hormones

Pancreatic islets

Insulin

• Produced by pancreas

Causes glucose to move into cells. Happens when glucose levels are too high

Hyperglycemia

High levels glucose

Glucagon

• Produced by pancreas

Promotes the release of glucose when blood glucose is too low

Hypoglycemia

Low levels of blood glucose

The two gonads

Ovaries and testes

What hormones are produced by the gonads

Sex hormones, testosterone, estrogen, progesterone

What makes testosterone

Interstitial cells of the testes

What makes estrogen and progresterone

Granulosa cells in ovarian follicles

Purpose of testerone

• Produced by gonads

Results in bone, muscle growth, and male sex characteristics

Estrogen

• Produced by gonads

Regulates the reproductive cycle and development

Progesterone

• Produced by gonads

Prepares uterus for pregnancy

Role of hypothalamus in Endocrine System

• Monitors hormone levels in blood

  • Stimulates endocrine gland to release more of a gland hormone

  • Stimulates endocrine to inhibit release hormone

Negative feedback

inhibiting secretion of hormone

Positive feedback

increasing secretion of hormone

infundibulum

a stalk or tunnel that connects the hypothalamus to the posterior pituitary gland

islets of Langerhans

• Small spherical clusters of endocrine cells located in pancreas

acromegaly

abnormal growth of bones, tissues and organs because of an over production of growth hormone starting in adulthood

Addison’s disease

disorder caused by decreased production of cortisol and aldosterone

adenoma

non-cancerous tumor of pituitary gland

Cushing’s syndrome

disorder caused by increased production of cortisol

diabetes

condition resulting from decreased insulin release or inability of the target cells to respond to insulin

endocrinologist

a healthcare provider specializing in the diagnosis and treatment of the endocrine system disorders

gigantism

disorder caused by an overproduction of growth hormone during child and adolescence

goiter

enlargement of thyroid

hypersecretion

too much release of hormone

hyperthyroidism

a condition in which the thyroid gland produces too much thyroid hormones

hypothyroidectomy

removal of thyroid gland

thyroiditis

inflammation thyroid

Hyperkalemia

High levels of potassium in blood