Bio - The endocrine system

Hormones of the Anterior Pituitary gland

- Adrenocorticotropic hormone (ACTH) - Thyroid stimulating hormone (TSH) - Follicle stimulating hormone (FSH) - lutienizing hormone (LH) - Prolactin - Growth hormone

Pancreas secretes

1. Alpha cells secrete glacogen - raises blood sugar levels - in the liver glucagon breaksdown glycogen into glucose 2. Beta cells secrete insulin - lowers blood sugar - promotes uptake of glucose to the cells - promotes conversion of glucose to glycogen 3. delta cells- somatostatin - inhibit insulin and glycogen

Four characteristics of the endocrine system

1. Hormones reach nearly every living cell (circulate in blood) 2. Each hormone acts on only certain cells (hormone receptor complex) 3. Endocrine control tends to be slower then nervous system control (must travel through blood) 4. The endocrine and nervous system can interact with eachother - the release of some hormones depend on the input from sensory neurons

2 categories of hormones

1. Steroid hormones 2. non steroid hormones

The following is a list of events involved in the activation of a cell by a steroid hormone. Which one of the following answers best represents the order in which the steps occur? 1. cellular response to the hormone 2. activation of a gene 3. formation of a hormone-receptor complex 4. diffusion of the hormone through a target cell membrane 5. production of a protein

4, 3, 2, 5, 1

Hormones of the posterior pituitary

Antidiuretic hormone (ADH) Oxytocin

Endocrine gland

Ductless organ that secretes their products into interstitial fluid, lymph and blood

An individual, driving through his neighborhood, suddenly jams on his car brakes to avoid hitting a child who runs into the road after a ball. A few seconds later, the driver finds that he is shaking and his heart is pounding. This is primarily due to the secretion of which one of the following?

Epinephrine and norepinephrine

Non tropic hormones

Has an affect on all cells of the body GH and prolactin

Hormones reach cells via the

Hypophyseal portal system

Uptake of blood glucose by liver cells is stimulated by

Insulin

Which one of the following is required in the diet in order for active thyroid hormones to be produced?

Iodine

PTH

Parathyroid hormone - removes calcium and phosphate from bones increases absorption of calcium from the GI tract - causes kidneys to retain calcium

Cortisol is a glucocorticoid that helps maintain blood glucose levels during fasting by

Promoting fat utilization

Adrenal cortex

Release of the sex hormones (testosterone and estrogen) steroid hormones (glucorticoid and mineral corticoids)

Calcitonin

Released by the thyroid gland to uptake calcium into the bones when calcium is high

ADH

Released form the posterior pituitary - reduces the amount of H20 lost from urine. - targets the kidneys - causes changes in cells permeability in kidney tubules to H20

Diabetes insipidus

Results of hyposecretion of ADH kidneys loose to much H20 symptoms: increase in thirst, increase in urination, dehydration and dry mouth, headache

Tropic hormones

Stimulate target organs (FSH, LH, ACTH, TSH)

Steroid hormones

Structurally related to cholesterol (lipid) therefore are lipid soluble and can cross the cell membrane - enter the cell, bind to intracellular receptor and activate genes that produce new proteins - produced by the cortex of the adrenal gland - cortisol and aldosterone - sex hormones - estrogen and progesterone

The endocrine system has certain characteristics that set it apart from the nervous system. Which one of the following characteristics is typical of the endocrine system, but NOT the nervous system?

The agents of communication are always chemical

What does the endocrine system control ?

The endocrine system triggers key physiololgical events, sexual maturation and puberty, childbirth and lactation and metabolism

The thymus produces two peptides that function to

aid in the maturation of T lymphocytes

A goiter results from low dietary iodine levels

because thyroxine cannot be made, which results in high levels of TSH

Adrenal medulla

controlled by the sympathetic nervous system - releases epinephrine and nor epinephrine

The ovaries of women function as endocrine organs by producing

estrogen and progesterone

Cortisol

glucorticoid - maintains blood glucose by breaking down fats and amino acids to use as glucose - also decreases inflammation by decreasing fluid loss from the capillaries

aldosterone

mineralcorticoid - regulates sodium and potassium - with ADH helps to maintain H20 balance - aldosterone acts on kidneys to absorb sodium and secrete potassium

Hypothalumus

small region in the brain that serves as a homeostatic control centre. important link between the nervous and endocrine system - recieves neural input about certain internal changes (temp changes, solute in-balance ) - monitors and controls the secretions of the pituitary gland

The endocrine system is a collection of ? that secrete ?

specialized cells, tissues, glands that produce or secrete circulating chemical messangers called Hormones

non steroid hormones

structurally related to proteins - not lipid soluble bind to receptors on the cell surface and cause cellular change inside cell with enzymes and ATP

oxytocin

target cells - uterus (contraction) mamary glands - eject milk

Hormones act upon specific target tissues because

target tissues display the appropriate receptor for a particular hormone

ACTH

targets the adrenal cortex - releases hormone glucorcoticoids for stress and glucose metabolism