CHP16: The endocrine system

What are the two main hormone classes?

1) Amino acid-based hormones (most hormones in the body)

2) Steroids

Hormones influence the activity of…

Target cells that have receptors for it

What are the chemical natures for amino acid-based and steroid hormones?

1) Amino acid-based: Water-soluble hormones (EXCEPT thyroid hormones)

2) Steroid: Lipid-soluble hormones

What are the receptor locations for water-soluble hormones?

1) Water-soluble: act on plasma receptors (CAN’T enter cell) that exert their effects through intracellular second-messenger systems

What are the receptor locations for lipid-soluble hormones?

Act on intracellular receptors (CAN enter cell) that directly activate genes, causing synthesis of new proteins. (Regulated with negative feedback)

What are the three types of control of hormone release? (HNH)

1) Humoral stimulus

2) Neural stimulus

3) Hormonal stimulus

What is Humoral Stimulus?

Hormone release caused by altered levels of certain nutrients or ions. (Chemical changes in BLOOD)

What is Neural Stimulus?

Hormone release caused by neural input

What is Hormonal Stimulus?

Hormone release caused by another hormone (tropic hormone)

What is the proper term for the Anterior Pituitary Gland?

Adenohypophysis

How do hormones travel to the Anterior Pituitary from the Hypothalamus?

Through the Hypophyseal Portal System

What are the three steps for the relationship of the Hypothalamus and Anterior Pituitary gland?

1) When stimulated, hypothalamus neurons secrete, releasing/inhibiting in the Hypophseal Portal system to the AP

2) The neurons then stimulate/release hormones in the anterior pituitary

3) Hormones are then secreted into a secondary capillary plexus, emptying them into general circulation to be sent elsewhere

What is the proper term for the Posterior Pituitary Gland?

Neurohypophysis

What are the 2 hormones that are related to the Hypothalamus and Posterior Pituitary gland?

1) Oxytocin

2) antidiuretic hormone (ADH)

How do hormones travel to the Posterior Pituitary from the Hypothalamus?

Through the Hypophyseal Tract

What are the 4 steps that describe the relationship of the Hypothalamus and the Posterior Pituitary?

1) Oxytocin or ADH and synthesized in the Hypothalamus

2) The hormones are then transported down the axons of the Hypophyseal tract to the Posterior Pituitary

3) Hormones are then stored in the posterior pituitary

4) Hormones are then released into bloodstream when stimulated by hypothalamus

What are the two functions of the Oxytocin Hormone?

1) Stretches a woman’s cervix when delivering a baby

2) Releases milk from mammary glands

(POSITIVE FEEDBACK)

What are target organs for the Oxytocin hormone?

1) Uterus

2) Breasts

What is the function of the Antidiuretic Hormone (ADH)?

To keep water in the body (decrease urine production), responds to low blood pressure

What is the target organ for ADH?

Kidneys

What is Diabetes Indipidus?

A syndrome marked by intense thirst and huge urine output

What is the major general function of the Parathyroid Hormone? (PTH)

To regulate and maintain regular calcium levels

What gland produces PTH?

The parathyroid gland

What are the 3 steps of Parathyroid hormone release?

1) activates osteoclasts to digest bone and release Calcium into the blood

2) Enhances reabsorption by the kidneys

3) Kidneys then activate Vitamin D which helps body absorb calcium from diet

Is the process of the Parathyroid positive or negative feedback acitivty?

NEGATIVE

What are the two part of the Adrenal Gland?

1) Adrenal Medulla

2) Adrenal Cortex

What does the Adrenal Medulla do and with what hormone?

Stimulates fight/flight, Norepinephrine hormone

What are the three layers (ZONAS) of the Adrenal Cortex? (GFR)

1) Zona Glomerulosa

2) Zona Fasciculata

3) Zona Recticularis

What hormone is related to the Zona Glomerulosa?

Aldosterone

What is the function of the Zona Glomerulosa?

Stimulates kidneys for reabsorption and water retention from a reaction of low blood pressure/volume

What hormone is related to the Zona Fasciculata?

Cortisol