Hormonal Regulation of Stress Response and Blood Glucose Chapter 9.3 McGraw-Hill Ryerson Biology 12 (2011)

Stress Management Intro It is the adrenal glands that help with stress management. They produce the hormones adrenalin (epinephrine) and noradrenalin (norepinephrine). Nervous system also produces adrenalin, so this is another link between the endocrine and nervous systems.

Adrenal Glands Both the stress regulating hormones are produced in the medulla of the adrenal glands. As you can see from the picture, the adrenal glands are similar to the kidneys in terms of general structure.

The Stress Response In times of stress, adrenalin and noradrenalin are released by the adrenal medulla into the blood stream. Adrenalin and noradrenalin are different in that noradrenalin goes to the brain and has psychoactive effects as well as physiological effects.

The Stress Response The release of adrenalin/noradrenalin into the blood stream will: Cause glycogen to be converted back into glucose in the muscles and liver. Cause heart rate and breathing rate to increase.

The Stress Response These responses boost the supply of oxygen and glucose to the muscles and brain, to enable as much aerobic cellular respiration as needed for the energy demands of the stressful situation. Non-important functions such as digestion will be suppressed during the stressful period.

The Stress Response Blood vessels constrict to help increase the flow of blood. The pupils of the eye dilate (get wider) as the body is trying to take in all the surroundings and get as much supplementary info as possible.

Meanwhile in the Adrenal Cortex… The adrenal cortex is producing the glucocorticoid steroid hormone, cortisol (hydrocortisone). Cortisol enters the bloodstream and immediately frees up amino acids in the blood. These amino acids are converted into glucose, which raises the blood sugar level. Cortisol prevents other tissues from taking in glucose thereby keeping glucose available in the blood for the brain and muscles. Insulin is also SUPPRESSED.

Fight or Flight All these reactions to stress by the body, triggered by hormones, will cause what is known as a ‘fight or flight’ response. The organism will either confront the stressor or will seek to get far away from the cause of the stress.

Long-term Stress In long-term stress responses, the hypothalamus sends a releasing hormone corticotropic releasing hormone (CRH) to the pituitary. The pituitary releases adrenocorticotropic hormone (ACTH) into the blood. ACTH reaches the adrenal cortex and causes it to send out its glucocorticoids (such as cortisol) and mineralocorticoids (such as aldosterone). These increase water and salt retention and can lead to high blood pressure.

SBI 4U: Metablic Processes LONG TERM STRESS Hypothalamus Anterior Pituitary Adrenal cortex Glucocorticoids Mineralocorticoids Cortisol Aldosterone (Negative feedback) Corticotropic Releasing Hormone ACTH Section 1.3

PANCREAS Digestive Enzymes Hormones: Insulin and Glucagon Pancreas cells produce: Digestive Enzymes Hormones: Insulin and Glucagon The hormones are produced in structures called the Islets of Langerhans (discovered by Paul Langerhans of Germany). approx. 2000 islets in the pancreas each islet has 2 types of cells: alpha and beta

INSULIN Liver converts glucose to glycogen produced in the Beta cells released when blood sugar is high (after a meal)‏ Stimulates uptake of glucose by making muscles, liver and other organs more permeable to glucose so it can be stored Liver converts glucose to glycogen Result: Decreases blood sugar level.

GLUCAGON liver breaks down glycogen into glucose and releases it produced in the alpha cells released when blood sugar levels are low (fasting) Stimulates release of glucose by organs into blood stream liver breaks down glycogen into glucose and releases it Result: Increase blood sugar level

Feedback loop for Blood Glucose http://static.ddmcdn.com/gif/diabetes-glucose-regulation.gif Feedback loop for Blood Glucose

A B

http://www.holistic-physician.com/articles/broch-bs.htm

DIABETES early degeneration of beta cells Chronic disease caused by insufficient production of insulin Type I (juvenile) (insulin dependent) - 10% early degeneration of beta cells Type II (adult) (non-insulin dependent, NIDDM) – 90% decreased insulin production or ineffective use of insulin produced. Gestational temporary condition of pregnancy that increases risk of diabetes in both mom and child Banting and Best – isolated insulin for treatment

Homework Pg 413 #2, 4, 6, 7, 9