Vertebrates

Hormones are

chemical signals or messengers (excite)

Hyposecretion

Abnormally reduced output

Hypersecretion

-Abnormally increased output

-Some cases, hormones secretes, but receptors do not respond

Hypothalamus Function

link nervous and endocrine systems anatomically and physiologically control most endocrine activity (directly or indirectly)

Pituitary gland: Location

connect to hypothalamus

Pituitary gland: Function

secretions control several other endocrine glands and tissues

Pituitary gland Structure

 human pituitary gland has two lobes: anterior and posterior

Posterior pituitary Structures

(connection with hypothalamus)

 -axons from neurons in hypothalamus extend into pituitary

Posterior pituitary: Hormones released:

neurohormones (peptide hormones) from hypothalamus

Hormone ADH: function and origin

antidiuretic hormone: Posterior Pituitary Gland

-kidney: water conservation

Hormone: Oxytocin: function and origin

Posterior Pituitary Gland

-stimulates uterine contraction, social behaviors (facilitates bonding with mother and infant), and facial recognition and trust

Explain the portal system

Anterior pituitary (A.P.):

hormones enter capillaries in hypothalamus, travel via portal vein to capillary bed in AP, from AP capillary bed diffuses out and contact cells

Anterior Pituitary Products (6)

-MSH; Melanocyte-stimulating hormone

-Prolactin

-Gonadotropic Hormones

-Thyroid-stimulating Hormone

-ACTH

-Growth Hormone

Hormone: MSH

Melanocyte-stimulating hormone: Anterior Pituitary

-stimulate melanin production in many vertebrates

Hormone: Prolactin

Anterior Pituitary

-produce milk in mammary glands

Hormone: Gonadotropic hormones

Anterior Pituitary

-ovaries and testies: produce gametes and hormones

Hormone: TSH

Thyroid-stimulating hormones: anterior Pituitary

-thyroid gland: increases rate or metabolism

Hormone: ACTH

Anterior Pituitary

-Adrenal Cortex: helps regulate fluid balance: helps body cope with stress

Hormone: GH

Growth Hormone: Anterior Pituitary

-Muscle, bone, and other tissues: promotes growth

Abnormal secretion of growth hormone (GH) (3)

Pituitary Dwarfism, Gigantism, Acromegaly

extreme GH deficiency during childhood

Pituitary Dwarfism

excessive GH amounts during childhood

Gigantism

hypersecretion GH during adulthood

Acromegaly: connective tissue thickens and bones may increase in diameter (hands, feet, and face)

Thyroid gland: Location

front of trachea, below larynx

Thyroid gland: hormones

T3 and T4 synthesized from tyrosine and iodine

Thyroid gland: Function

-metabolic rate, regulate proteins for cell differentiation, Ca2+ metabolism (later)

Thyroid gland: heat

Heat production (cold snap example)

-Cold temperature

-Hypothalamus increases secretion of TSH-releasing hormone which increases heat production

Thyroid disorders:

-Hypothyroidism (cretinism and myxedema)

-Hyperthyroidism (graves’ disease and goiter)

Infancy and childhood: Low metabolic rate,  may occur (retarded mental and physical development) 

Cretinism

In adulthood characterized by slowing down of physical and mental activity 

Myxedema

an autoimmune disease causing high metabolism, weight loss, and irritability

Graves’ disease

Enlarged thyroid: result is either hyposecretion or hypersecretion of hormones

Goiter

Parathyroid Glands: Location

surround thyroid gland

Parathyroid Glands: Secretion

parathyroid hormone (PTH)  

PTH function

works antagonistically to calcitonin (thyroid hormone) in regulating Ca2+ level

Regulation of calcium homeostasis:

-Parathyroid hormone: stimulate the removal of calcium from bone/urine and uptake of calcium in digestive tract

-Calcitonin (thyroid): take excess and but back in bone and no longer uptake

-Calcitonin and PTH regulate Ca2+ level

-Negative feedback cycle

Pancreas: Function (mixed)

Endocrine (insulin and glucagon) (alpha-a-glucAgon) (beta-insulin)

Exocrine (digestive enzymes)

Endocrine function of Islets of Langerhans in pancreas

Alpha cells - glucagon

Beta cells - insulin

Insulin stimulates…

-Glucose uptake from blood

-Inhibits glucose release from liver

-Result: Free glucose level reduced

Glucagon stimulates…

-Glycogenolysis: Liver converts glycogen to glucose

-Gluconeogenesis: Production of glucose from non-carbohydrates

• Result: Glucose level rise

group of related disorders characterized by high blood glucose level. Most common endocrine disorder (may lead to blindness and possibly death)

Diabetes mellitus

Decline in number of beta cells, injections of insulin, Autoimmune disorder

Type 1 [Insulin dependent]

Lack functional receptors on target cells, Regulation by exercise and diet

Type II [insulin independent]

Metabolic disturbances in diabetes mellitus (50

- Decreased use of glucose: cells have difficulty taking up glucose (glucose in urine)

-Dehydration: water follows glucose osmotically into urine

-Increased fat mobilization: energy source needed (ketone bodies may accumulate)

-Electrolyte imbalance: ketones take Na, K, and other cation with them not urine

-Increased protein use: another energy source and often = thin, emaciated

Low blood glucose concentration

Hypoglycemia

Hypoglycemia Develpoment

 Delayed response to carbohydrate (glucose) intake followed by overreaction of islets

- Insulin hypersecretion: Glucose levels fall, and individual becomes drowsy, uncoordinated or unconscious

Can develop is diabetic receives too much insulin

Serious Hypoglycemia (insulin shock)

Location of adrenal glands:

above kidneys

Structure of adrenal glands

Adrenal cortex and adrenal medulla

Adrenal cortex Location and hormones

outer tissue region

-Androgens: precursors to sex hormone testosterone and estradiol 

-Aldosterone: acts on kidneys to regulate Na+ and K+ to maintain blood volume and pressure  

-Cortisol: stimulates glucose production by liver cells during stress

Adrenal medulla Location and hormones

 inner tissue region

- epinephrine and norepinephrine

Adrenal medulla hormones increase….

Metabolic rate, Circulation of brain, muscles, and heart, Conversion of glycogen to glucose (glycogenolysis)

Hormones of medulla Controlled by s

sympathetic nervous system (hypothalamus)

-During stress, hypothalamus signals sympathetic neurons triggers hormone release