Chapter 31 Endocrine Control

Difference between endocrine and exocrine The endocrine system controls the body activities by producing chemical substances called ______________which are secreted by ductless glands known as __________________ Exocrine gland secrete their products into ducts or channels, that carry them either to the outside of the body or into _____________________.

What Are Animal Hormones? Animal hormones: ____________________________ ________ that are secreted by __________________ Distributed by the _______________; Typically act at ___________________from their source Only cells with the appropriate ________________ (target cells) can respond to a specific hormone

Categories of Hormones Two major categories of hormones: ______________________-derived hormones (________)

Categories of Hormones (cont’d.) Amino acid-derived hormones: bind to receptors at the __________________of a target cell Initiates __________________ signaling cascade that brings about the target cell’s response Often results in the activation of an ___________ Example: glucagon binds to receptor; causes activation of glycogen-degrading enzyme

Categories of Hormones Steroid hormones: synthesized from ____________________ Directly affects gene expression Diffuses into a target cell (why?) and forms a hormone–receptor complex Hormone–receptor complex: _____________________________________________________________________________________________

Hormone Receptor Function Many hormones target more than one type of cell Elicit a ________________response in each cell type Example: antidiuretic hormone (ADH) Affects urine formation in the ________________ Triggers smooth muscle contraction in ___________________

What Are the Components of the Human Endocrine System? Endocrine glands: aggregations of epithelial cells that produce and secrete ________into the ______ Collectively make up the __________________________ Portions of the ____________system and ________ system are closely linked Most organs respond to hormones and signals from the ________________________

Endocrine System Figure 31.2 {Animated} Major glands of the human endocrine system. Other vertebrates typically have the same glands.

What Are the Components of the Human Endocrine System? Table 31.1 Examples of Human Endocrine Glands, Their Hormones, and Hormone Actions

How Does the Hypothalamus Interact With the Pituitary Gland? Hypothalamus: main center that controls the ____________________________________ Lies deep inside the forebrain and connects with the ____________________________ anterior lobe of pituitary posterior hypothalamus

Posterior Pituitary Function Neurosecretory cells in the hypothalamus synthesize _____________ hormones These hormones are transported along _________in the posterior pituitary An action potential triggers the release of hormone into the _____________ Posterior pituitary releases two hormones: ____________________________(____) ____________________________

pituitary function Figure 31.4 {Animated} Pituitary function.

Anterior Pituitary Function The anterior pituitary makes ___________ hormones and secretes them in response to hormones from the __________________________ Anterior pituitary hormones: ________________________________________________ _________________________________________________

Hormonal Growth Disorders Growth hormone production surges during _____________, causing a growth spurt, then declines with __________ _______secretion of growth hormone during childhood leads to pituitary ___________________ ___________growth hormone during childhood can cause pituitary _______________

What Is the Role of the Pineal Gland? Pineal gland: lies deep inside the brain; secretes the hormone ___________under low-light or dark conditions ____________: _________________________________________

What Are the Thyroid and Parathyroid Glands? Thyroid gland: endocrine gland located in the base of the neck Thyroid hormone (triiodothyronine and thyroxine): increases metabolic activity The anterior pituitary gland and hypothalamus regulate thyroid hormone secretion Decline in thyroid hormone causes hypothalamus to secrete thyroid-releasing hormone (TRH) TRH causes the anterior pituitary to secrete thyroid-stimulating hormone (TSH) TSH stimulates secretion of thyroid hormone

What Are the Thyroid and Parathyroid Glands? STIMULUS RESPONSE Hypothalamus TH declines below a set point 1 TRH 4 Anterior Pituitary TSH 2 Figure 31.6 Control of thyroid hormone (TH) secretion. Thyroid Gland 3 TH secretion increases and metabolic rate rises.

Hormonal Regulation of Blood Calcium Level There are four parathyroid glands on the thyroid’s _____________________surface Parathyroid hormone (PTH): ______________________ _________________________________________________ Calcitonin: ______________________________________ _________________________________________________; opposes the actions of PTH

What Are the Roles of the Adrenal Glands? Adrenal gland: endocrine gland that is located atop the __________________ Adrenal cortex: __________________________________ Examples: Aldosterone: acts in _______________and makes urine more concentrated Cortisol: affects ______________and ______________________ Adrenal medulla: responds to stimulation by releasing __________________and ______________into the blood Brings on ____________________________

What Are the Roles of the Adrenal Glands? (cont’d.) STIMULUS RESPONSE Blood level of cortisol declines. Hypothalamus 1 CRH 4 Anterior Pituitary adrenal cortex Rise of cortisol level in the blood inhibits the secretion of CRH and ACTH. 2 ACTH adrenal medulla Adrenal Cortex 3 Cortisol secretion increases and has the following effects: Figure 31.8 Control of cortisol secretion. Cellular uptake of glucose from blood slows in many tissues, especially muscles (but not in the brain). Protein breakdown accelerates, especially in muscles. Some of the amino acids freed by this process get converted to glucose. Fats in adipose tissue are degraded to fatty acids and enter blood as an alternative energy source, indirectly adrenal cortex adrenal medulla kidney conserving glucose for the brain. kidney

Hormones, Stress, and Health Long-term elevation of cortisol is unhealthy (example: Cushing’s syndrome): Interferes with _____________, _____________, and ______________function Raises the risk of _________________________________ Abnormally low levels of cortisol (example: Addison’s disease) ___________, _____________, ______________, and _____________________________________

What Are Sex Hormones? Sex hormones: ____________hormones produced by the _________________ Essential to ___________________________function Influence secondary sexual characteristics ______________________________________________________________________________________________________________

What Are Sex Hormones? Testosterone: responsible for development of __________________________and secondary sexual characteristics Estrogens: function in ________________and cause development of ______________secondary sexual characteristics Progesterone: prepares a female body for ______________and helps ______________________

What Are Sex Hormones? Figure 31.10 Control of sex hormone secretion.

How Does the Pancreas Regulate Blood Sugar? Pancreas: lies in the ______________cavity, behind the _____________ Exocrine cells: secrete _________________________ into the small intestine Endocrine cells: grouped in clusters called pancreatic islets (e.g., ______cells and _______cells)

How Does the Pancreas Regulate Blood Sugar? (cont’d.) Beta cells secrete _________when blood glucose levels ___________ Insulin causes its target cells to ___________________ _________________________________ Encourages synthesis of fats and proteins and inhibits their breakdown _________________________________________ Alpha cells secrete ___________when blood glucose levels ____________ Glucagon binds to receptors on liver cells: activates enzymes that break __________ into ________subunits ___________________________________________

Hormones and glucose metabolism Figure 31.11 {Animated} Above, the location of the pancreas. Right, how cells that secrete insulin and glucagon work antagonistically to adjust the level of glucose in the blood.

How Does the Pancreas Regulate Blood Sugar? The regulation of blood glucose is disrupted in diabetes mellitus Type 1 diabetes: ______________________________ _____________________________________________ Symptoms usually appear in ____________and ______________ Type 2 diabetes: ______________________________ ______________________________ Symptoms typically start in ___________________

How Does the Pancreas Regulate Blood Sugar? (cont’d.) Insulin pump. This device delivers insulin into a diabetic’s body to maintain blood glucose within normal levels. Figure 31.12 Insulin pump. This device delivers insulin into a diabetic’s body to maintain blood glucose within normal levels.

Do Invertebrates Have Hormones? Some components of the endocrine system occur in invertebrates Example: __________, ___________, and __________ make ____________hormones Invertebrates do not have the same glands as vertebrates do, but they produce the homologous hormones in other glands Example: octopi produce _________, __________, and ___________ in a gland near their eye

Do Invertebrates Have Hormones? Hormone-signaling systems unique to invertebrates have also evolved Example: a hormone unique to arthropods called ecdysone controls molting (periodic shedding of the exoskeleton)