Test #1

Question 0

What are the key characteristics of the endocrine system?

Answer 0

Regulate and maintain body functions by synthesizing and releasing hormones and chemical messengers.

Areas of control and integration responses to: -stress and injury-growth and development-absorption of nutrients-energy metabolism-water and electrolyte balance-reproduction-birth-lactation

Glands secrete chemical messengers (hormones) into circulatory system

Regulate activities of body structures

Question 1

Why is the endocrine system also referred to as neuroendocrine?

Answer 1

The endocrine and the nervous system are very closely related and that is their collective name. Neural control centers in the brain control glands.

Question 2

What are the characteristics of hormones?

Answer 2

Produced in small quantities

Secreted into intercellular space

Transported some distance in circulatory system

Acts on target tissues elsewhere in body

Question 3

Half life?

Answer 3

The length of time it takes for half a dose of substance to be eliminated from the circulatory system.

Long half life: regulate activities the remain at a constant rate. Usually LIPID SOLUBLE and travel in plasma attached to proteins.

Short half life: water-soluble hormones as proteins, epinephrine, norepinephrine. Have rapid onset and short duration.

Question 4

What is the main mechanism of control of hormonal secretion?

Answer 4

Negative feedback systems.

Most aren’t released at a constant rate, but their secretion is regulated by three different methods: -the action of a substance other than the hormone- neural control of endocrine gland - control of secretory activity of one endocrine gland by hormone or neurohormone secreted by another endocrine gland

Question 5

What is hypothyroidism?

Answer 5

A disorder in which there is not enough stimulation of T3 and T4. Though TSH levels will be high when tested in blood.

Question 6

How is hypothyroidism diagnosed?

Answer 6

A blood test is used, if TSH levels are found to be high with low T4 and T3 then it’s diagnosed

Question 7

How is hypothyroidism treated?

Answer 7

Hormonal supplementation. If cancer or an autoimmune disease like Hashimotos destroys the thyroid gland it may have to be removed.

Question 8

What’s is the most common cause of hypothyroidism?

Answer 8

Hashimotos and other autoimmune diseases

Question 9

How is blood glucose regulated?

Answer 9

By insulin which decreses blood glucose levels by stimulating transport of glucose from the blood to tissues (muscles 80%). Thus increasing uptake of glucose and amino acids in cells.

And by glucagon which increases the breakdown of glycogen by liver and skeletal muscle into glucose that releases into the circulatory system.

Somatostatin which inhibits the secretion of insulin and glucagon

Question 10

How is insulin regulated?

Answer 10

When blood glucose is high insulin is stimulated to be secreted and when blood glucose is normal or low somatostatin inhibits secretion.

Question 11

Relationship between blood glucose, insulin, skeletal muscles and type II diabetes?

Answer 11

People with type II diabetes are insulin resistant so insulin has little effect on lowering blood glucose. However glucose will continue to be synthesized by the muscles and keep increasing blood glucose levels.

Question 12

What are the symptoms of diabetes?

Answer 12

Type I - polyuria (frequent urination), polydipsia (increased thirst), polyphagia (increased hunger), and weight loss.

Type II - same as Type I but are less intense and many times ignored.

Question 13

What are the key differences between membrane bound and lipid soluble hormones?

Answer 13

Membrane bound receptors bind to water-soluble or large-molecular-weighted hormones on membrane

Intracellular receptors bind to lipid soluble hormones

Question 14

How can effects of hormones that are secreted in such a minute amount be so powerful?

Answer 14

The cascade effect!!

Question 15

What hormones are under the control of the hypothalamus?

Answer 15

Growth Hormone releasing hormone (GHRH) - targets the anterior pituitary cells telling them to increase the secretion of growth hormone.

Growth hormone inhibiting hormone (GHIH) or somatostatin - targets the anterior pituitary cells telling them to decrease secretion of growth hormone.

Thyrotropin releasing hormone (TRH) - targets anterior pituitary cells and tells them increase the secretion of thyroid stimulating hormone.

Corticotropin releasing hormone (CRH) - targets the anterior pituitary cells telling them to increase secretion of adrenocorticotopic hormone.

Gonadotropin releasing hormone (GnRH) - targets anterior pituitary cells telling them to increase the secretion of luteinizing hormone and follicle stimulating hormone.

Prolactin releasing hormone (PRH) - targets anterior pituitary cells telling them to increase prolactin secretion.

Prolactin inhibiting hormone (PIH) - targets anterior pituitary cells telling them to decrease prolactin secretion.

Question 16

What hormones are under the control of the anterior pituitary?

Answer 16

Growth hormone (GH) - promotes growth and regulation of metabolism of carbs, proteins and lipids

Prolactin (PRL) - promotes the growth of the mammary glands and lactation in females

Thyroid-stimulating hormone (TSH) - stimulates the thyroid to produce T3 and T4

Melanin stimulating hormone (MSH) - stimulates the the secretion of melanin in skin and hair

Adrenocorticotropic hormone (ACTH) - stimulates the secretions of corticoids

follicle stimulating hormone (FSH) - reproductive function, growth and development

Luteinizing hormone (LH) - reproductive function, stimulates ovulation, development of corpus luteum in females and devlopment of androgens in males

Question 17

What are the hormones under control of the posterior pituitary and what is the key action of them?

Answer 17

antidiuretic hormone (ADH) - increased water reabsorption resulting in less urine

Oxytocin - contractions increase in uterus and ejection of milk from lactating breast

Question 18

What are the physiological effects of cortisol?

Answer 18

Increase in fat and protein breakdown, glucose levels and antiinflammatory effects

Question 19

What is hypocortisolism?

Answer 19

An insufficiency of adrenal glands. Causes fatique, weakness, anorexia, nausea, vomiting

Question 20

How is hypocortisolism treated?

Answer 20

Corticoids, corticosteroids

Question 21

What are the effects of aging on the endocrine system?

Answer 21

Gradual decrease in secretory activity of some glands

Decrease in GH, less decrease in those that exercise

Androgens decrease

Melatonin decreases

Thyroid hormones decrease and loss of muscle receptors, exercise helps both

Kidneys secrete less renin

familial tendency to develope type II diabetes increases with age

Question 22

What are the functions of digestive system?

Answer 22

• ingestion: introduction of food into stomach
• mastication: chewing, chemical digestion requires large surface area so breaking down large particles mechanically facilitates chemical digestion
• propulsion: DEGLUTITION - swallowing PERISTALSIS - moves a wave of circular smooth muscle through digestive tract. A wave of circular smooth muscle relaxation moves ahead the bolus of food or chyme allowing the digestive tract to expand. Then a contraction wave of the circular smooth muscles behind the bolus of food or chyme propels it through the tract. MASS MOVEMENTS in large intestine
• mixing: segmental contractions that diffuse and break apart bolus
• secretion: lubricate, liquefy and digest - MUCUS - secreted along entire digestive tract, protects from from mechanical digestion, acid and other enzymes - WATER - makes food easier to digest and absorb - BILE - emulsifies fat - ENZYMES - chemical digestion
• digestion - Mechanical and Chemical
• absorption - movement from tract into circulation or lymph
• elimination - waste product removed from body, feces, defecation

Question 23

Mastication reflex?

Answer 23

Medulla oblongata, descending pathways fro t he cerebrum provide conscious control, this is basic movement in chewing

Question 24

What are the three pairs of salivary glands, their secretions and functions?

Answer 24

Parotid (largest, serous glands)

Submandibular (mixed, + serous)

Sublingual (smallest, mixed, + mucous)

These all produce saliva: prevents bacterial infections (lysozyme IgA), lubrication, contains salivary amylase (breaks down starches), enamel protection (HCO3-)

Question 25

What are the three phases f deglutition? (Swallowing)

Answer 25

VOLUNTARY - bolus of food moved by tongue from the oral cavity to pharynx.

PHARYNGEAL - Reflex - upper esophageal sphincter relaxes (group of striated muscles), elevated pharynx opens esophagus, food pushed into esophagus, epiglottis is tipped posteriorly, larynx elevated to prevent food from passing into larynx.

ESOPHAGEAL - Reflex - as food approaches the stomach, lower esophageal sphincter (smooth muscle - not anatomically distinct, constricted by maintained to us) relaxes and opens.

Question 26

What are the 3 layers of the stomach and the purpose for them?

Answer 26

Outer longitudinal, middle circular, inner oblique

these muscles working in different directions ensure gastric juices and food mix properly.

Question 27

HCl production and how to treat an excess?

Answer 27

Produced in parietal cells, carbon dioxide is diffused into parietal cell and enzyme carbonic and hydrase catalyze a reaction between between carbon dioxide and water to form carbonic acid. This dissociates into into bicarbonate ion and hydrogen ion, bicarbonate ion is transported back into bloodstream. As bicarbonate goes out it is exchanged with a chloride ion into the cell. Hydrogen ions are transported into gastric duct and chloride ions diffuse with them. Potassium is counter transported into parietal cell in exchange with hydrogen this produces the hydrochloric acid.

Treated by antagonists to histamine receptors and or inhibitors of the proton pump.

Question 28

What are the phases of gastric secretion?

Answer 28

Cephalic phase - any sense or thought of food (vagus nerve) stimulate the release of HCl and Pepsin in the stomach also gastrin in lower part which travels in blood and further stimulates secretion

Gastric - food has entered the stomach, activates a reflex from the medulla oblongata and has stimulators effect directly on gastric glands this further continue release of HCl and pepsin

Intestinal phase - chyme has entered the due denim so secretion is no longer needed, when chyme contains lipids from digestion of fats or contains enough HCl to bring Ph below 2 gastric secretion is inhibited, lipids and hydrogen ions inhibit secretions by three simultaneous actions first impulses go to medulla oblongata to decrease parasympathetic secretion of gastric glands, secondly they set up reflexes in wall of gut that decrease secretion, third they cause the release of three local hormones that travel through circulation to gastric glands to inhibit secretion

Question 29

What is the main cause of gastritis and duodenal ulcers (H. Pillory)?

Answer 29

Mucosal lining digested by acid

Presence of H. Pylori in stomach

The role of H. Pylori in ulcers, gastritis and even cancer was recognized

Question 30

How can H. Pillory survive in 2 pH?

Answer 30

It hides in the mucous of the stomach while still being able to move with its flagellae