Human Physiology: Chapter 6

Control of hypothalamic tropic hormone release

Reseats daily cycle based on light stimulus - Neural input - Hormonal

Neural input

Suprachiasmatic nucleus of the hypothalamus

Skin and kidneys & liver:

are involved in the production of 1,25-Dihydroxy vitamin D3, which regulates blood calcium levels

Endocrine Pancreas

consisits of cell clusters called islets of langer hans, which are scattered through the pancrease in spaces between the ducts

Pineal gland

is like the coach that is calling the plays up in the booth in the NFL • Receiving the talk from the brain • Pineal gland then goes into the

Hypothalamus

is part of the brain with many functions in addition to its role as an endocrine gland because it secretes several hormones most of which affect the pituitary gland, a pea-sized structure connected to the hypothalamus

Fat:

leptin ("satiety hormone) (feeling of fullness)

Anterior lobe

of the pituitary gland and the cells of the hypothalamus the control it secrete primarily topic hormones which are hormones that regulate the secretion of other hormones.

Posterior lobe

of the pituitary gland contains neural tissues consisting of the axon terminals of neurons originating in the hypothalamus

Primary Endocrine organs

organs whose primary function is the secretion of hormones. Beginning with the hypothalamus and pituitary gland.

Synergism

pertaining to a process in which the net effect greater than the sum of the individual effects - Effects of 2 hormones favor each other but the net effect exceeds the sum of individual effects - Ex: the effects of glucagon, cortisol and epinephrine on blood glucose - When you combine all those effects you preform a lot better while doing your exercise

Pituitary-

primary ndocrine gland connected to the hypothalamus at the base of the brain, divided into the anterior pituitary and posteiror pituitary. • Tropic and sex hormones

Melatonin secretion is known to be

regulated primarily by the input from the suprochiusmatic nucleus of the hypothalamus, the primary cneter in the brain for establishing Canadian rhythms.

Thyroid

s a butterfly-shaped strucutre located on the ventral surface of the thrachea • metabolism

Heart

secretes atrial natriuretic peptide (ANP), which regulates sodium reabsorption by the kidneys and reduces BP. • atrial natriuretic peptide • ANP reduces blood pressure

GI tract

secretes several hormones that are important in regulating the digestion and absorption of food, including gastrin, secretion, and chole cytokine. • several hormones released (know hormones in GI tract) • Cholecystokinin • Secretin • Gastrin

All of the brain tissues basically feeds into your ______________

thalamus

The function of the melatonin is

that its important in establishing the circadian rhythm (a daily rhythm coordinating body activates to the day-night cycle)

Sex hormones

• Are secreated by cells in the zona fasciulata and zona reticulars (and by the gonads). Sex homrones regulate repordcutive functions and a variety of other processes. • (androgens) Regulates sex drive

Pituitary

Means to produce or output • Primary endocrine gland

Pineal

which is located within the brain and is composed of epitehial tissue that secretes the hormone melatonin • Circadian rhythm

Pineal gland

which is located within the brain and is composed of epithelial tissue that secretes the hormone melatonin • Granular tissue in the brain • Secretes melatonin Involved in circadian rhythms Important in timing of seasonal processes in mammals

Glucocorticoids (cortisol) (regulates response to stress)

• (Primiary cortisol) are secreted mainly by cells in the zona fasculata and zona reticularis. Cortisol regulates the body's response to stress; protein, carbohydrate, and lipid metabolism in a variety of tissues, and blood glucose levels. Cortisol is regulated by the CRH-ACTH-cortisol axis • Increases blood glucose (glyconeogensis), metabolism • Regulates body's response to stress & metabolism

Compared to the posterior lobe, the anterior lobe is more like a

"typical" endocrine gland, in that hormones are synthesized and secreted by cells located in the pituitary gland.

Hormones of Posterior Pituitary

- Antidiuretic hormone (ADH)- also called vasopressin. - Oxytocin (swift childbirth)

Pancreas

- Blood glucose regulation

There are approximately twice as many beta cells as alpha cells in the islets

- Insilin decreases blood glucose levels by promoting its uptake into cells mad concersion to glycogen • Glycogen increases blood glucose levels by promoting glycogenolysis and glyconeogennsis • Alpha cells: glucagon ~ raise blood glucose • Beta cells: insulin ~ lower blood glucose- Anabolic hormone (insulin) • Delta cells: somatostatin ~ regulate pancreas & digestion

The adrinal adrenocorticoids include three types of homrones

- Mineralocorticoids (aldosterone) (raise blood pressure) - Glucocorticoids (cortisol) (regulates response to stress) - Sex hormones

Key organs and hormones of the Endocrine system

- Pineal - Hypothalamus - Pituitary - Thyroid - Adrenal - Pancreas - Sex glands

Hypothalamic-Pituitary Portal System

Portal system • Links 2 capillary beds • Exchange between blood and tissue occurs in the capillaries

Hypothalamus

a region at the base of the brain that regulates autonomic functions and secretes several homrones, most of which regulate secretory acivity of the pituitary. • Link endocrine & nervous

Antagonism

in the endocrine system, when one hormone opposes the actions of another hormone • Effects of hormones oppose each other - Ex: glucagon vs insulin - Glucagon increases blood glucose levels - Insulin decreases blood glucose levels

Liver

insulin-like growth factors (somatomedins)

Adrenal

located above the kidneys - Fight or flight

Adrenal Medulla

• Epinephrine (fight or flight), norepinephrine (stimulatory hormone) • Contains chromaffin cells and secretes catecholamines; approximately 80% of the secreted homrones is eoinephrine (also called adrenaline) approximaletly 20% is norepinephrine , less than 1% is dopamine. Epinephrine is released during times of stress.

Mineralocorticoids (aldosterone) (raise blood pressure)

• Exclusively by cells in the zona glomerulosa. Aldosterone regulates sodium reabsorption and potassium secretion by the kidneys. • Maintains sodium and excreted potassium= retain water • Regulates sodium and potassium levels

Humoral Control of Hormone

• Humoral/ Endocrine control of hormones • Sensory receptors that are detecting the error signals are the beta cells Beta cells and resorting the blood glucose and is the integrating center • Blood glucose goes down and tells beta cells to stop producing insulin (30 mins after a meal)

Secondary endocrine organs

• In addition to fulfill their primary function, many organs of the body secrete hormones - Heart - Kidneys - GI track - Liver - Skin and kidneys - Fat

The islets of langerhans are the source of two major hormones, each of which secreted by a different cell type:

• Insiluin, which is secreted by beta cells (B cells) (lowers blood glucose) • Glucagon, which is secreted by alpha cells (A cells) (raises blood glucose)

Polar system

• Links two capillary beds • Exchange between blood and tissue occurs in the capillaries

Hormonal

• Melatonin secreted by the pineal gland • Negative feedback

Hormones control by a circadian rhythm

• Neural control of circadian rhythm • Hormonal control of circadian rhythm • Circadian rhythm- (a daily rhythm coordinating body activities to the day-night cycle). For instance, melatonin secretion is known to be regulated primarily by input from the suprachiasmatic nucleus of the hypothalamus, the primary center in the brain for establishing circadian rhythms. • All tropic hormones of hypothalamus affected by circadian rhythm from suprachismatic nucleus

Calcitonin

• Regulate calcium levels in the blood • Decreases blood glucose levels

Antidiuretic hormone (ADH)- also called vasopressin.

• Synthesised primarily in the periventricular nucleus • Water balance and osmolality. (raises blood pressure) • Hormone secreted by the posterior pituitary that regulates water reabsorption by the kidneys, also called vasopressin. • Water balance and osmolality (raises blood pressure)

Oxytocin (swift childbirth)

• Synthesized primarily in the supraoptic nucleus • Facilitates uterine contraction lactation • Hormone secreted by the posterior pituitary that regulates contractions of the uterus and the flow of milk from the breast, functions as a neurotransmitter in some neurons. • Facilitates uterine concentration, lactation • Role in orgasm, social recognition, pair bonding, anxiety, and maternal behaviours • "bonding hormone"

2 thyroid hormones

• T4: tetraiodthyronie (thyroxin) • T3: triiodothyronine • Regulate the bodys metabolic rate and and are necessary for nromal growth and development • Regulates metabolism- increases metabolim, protein synthesis, protein fat, CHO metabolism • In volved in growth and differnentiation all tissues

Neurosecretory cells have releasing and inhibition hormones

• They can turn on/off the hormones from the anterior pituitary • They go to tropic hormones which have great effects on the body • Beasts, thyroid gland, adrenal glands

Parathyroid hormone (PTH)

• an important regulator of calcium levels in the in the blood. Parathyroid hormones act on the bones, kidneys and intestines to increase blood calcium levels. • Increases calcium levels in the blood

Kidneys

• secretes erthopointin, which stimulates production of red blood cells by the bone marrow. • erythropoietin • EPO increases red blood cells