FINALS LEC 2: ENDOCRINE SYSTEM Flashcards
Second messenger system of the body.
- Uses chemical messages (hormones) that are released into the blood.
ENDOCRINE SYSTEM
Hormones control several major processes: (such as)
- Reproduction
- Growth and development
- Maintenance (homeostasis)
- Regulation of metabolism
- Comes from a Greek word meaning “to arouse”
- Produced by specialized cells (secrete hormones into extracellular fluids)
- Blood transfers hormones to target sites
- These hormones regulate the activity of other cells
HORMONES
Chemical Classification of hormones:
(proteins, peptides, amines)
AMINO ACID - BASED HORMONES
STEROIDS
PROSTAGLANDINS
AMINO ACID - BASED HORMONES
Chemical Classification of hormones:
(cholesterol)
AMINO ACID - BASED HORMONES
STEROIDS
PROSTAGLANDINS
STEROIDS
Chemical Classification of hormones:
(highly active lipids)
AMINO ACID - BASED HORMONES
STEROIDS
PROSTAGLANDINS
PROSTAGLANDINS
MECHANISM OF HORMONE ACTION
Hormones affect only CERTAIN TISSUES/ORGANS (target cells or organs)
T OR F?
TRUE
MECHANISM OF HORMONE ACTION
Target cells MUST HAVE SPECIFIC PROTEIN RECEPTORS
T OR F?
TRUE
MECHANISM OF HORMONE ACTION
Hormones binding DOES NOT INFLUENCES the working of the cells.
T OR F?
FALSE
MECHANISM OF HORMONE ACTION
Effects caused by hormones:
- Changes in plasma membrane permeability/electrical state
- Synthesis of proteins, such as enzymes
- Activation/inactivation of enzymes
- Stimulation of mitosis
- Promotion of secretory activity
MECHANISM OF HORMONE ACTION
- DIFFUSE through the plasma membrane of target cells
- Enter the nucleus
- Bind to a specific protein within the nucleus
- Bind to specific sites on the cell’s DNA
- Activates genes that result in synthesis of new proteins
a. Direct Gene Activation: STEROID HORMONE MECHANISM
b. Second-Messenger System:
NONSTEROID HORMONE MECHANISM
Direct Gene Activation: STEROID HORMONE MECHANISM
MECHANISM OF HORMONE ACTION
- Hormone BINDS to a membrane receptor and it does not enter the cell
- Sets off a series of reactions that activates an enzyme catalyzing a reaction that produces a second messenger molecule
- Oversees additional intracellular changes to promote a specific response
a. Direct Gene Activation: STEROID
HORMONE MECHANISM
b. Second-Messenger System:
NONSTEROID HORMONE MECHANISM
Second-Messenger System:
NONSTEROID HORMONE MECHANISM
CONTROL OF HORMONE RELEASE
- Hormone levels in the blood are maintained by __________________
NEGATIVE FEEDBACK
CONTROL OF HORMONE RELEASE
- A stimulus/low hormone levels in the blood TRIGGERS the release of more hormones
T OR F?
TRUE
CONTROL OF HORMONE RELEASE
- Hormone release stops once an appropriate level in the blood is reached
T OR F?
TRUE
THE MAJOR ENDOCRINE ORGANS
- Approximately the size of pea
- Hangs by a stalk from the hypothalamus
- Protected by the sphenoid bone
- Has 2 functional lobes
PITUITARY GLAND
PITUITARY GLAND 2 FUNCTIONAL LOBES
- glandular tissue
- “Master endocrine gland”
- Releases 6 hormones (2 affect nonendocrine targets & 4 stimulate other
endocrine glands [tropic hormones])
Proteins (or peptides)
Act through second-messenger
systems
Regulated by hormonal stimuli,
mostly negative feedback
ANTERIOR PITUITARY
POSTERIOR PITUITARY
ANTERIOR PITUITARY
PITUITARY GLAND 2 FUNCTIONAL LOBES
- nervous tissue
- Not and endocrine gland, acts only as a
storage area for hormones made by
hypothalamic neurons
1. Oxytocin
2. Antidiuretic hormone (ADH) or
vasopressin
ANTERIOR PITUITARY
POSTERIOR PITUITARY
POSTERIOR PITUITARY
THE MAJOR ENDOCRINE ORGANS
- Hormonal release of the anterior pituitary is controlled by releasing hormone & inhibiting hormones produced by ___________
HYPOTHALAMUS
THE MAJOR ENDOCRINE ORGANS
- Found at the base of the throat
- Consists of 2 lobes & a connecting isthmus
- Produces 2 hormones:
a. THYROID HORMONE (major metabolic hormone
b. CALCITONIN
THYROID GLAND
THE MAJOR ENDOCRINE ORGANS
- TINY MASSES on the posterior of the thyroid
- Chief cells secrete parathyroid hormone
(chemical class: PEPTIDE)
Stimulate osteoclasts to remove calcium from bone
Stimulate the kidneys & intestine to absorb more calcium
Raise calcium levels in the blood
PARATHYROID GLANDS
THE MAJOR ENDOCRINE ORGANS
- Sit on top of the kidneys
- has 2 glands:
Cortex and Medulla
ADRENAL GLANDS
ADRENAL GLANDS
- outer glandular region;
produces 3 major groups of steroid
hormones (CORTICOSTEROIDS)
CORTEX
ADRENAL CORTEX
CHEMICAL CLASS: STEROIDS
MAJOR ACTIONS: Increase blood glucose
REGULATED BY: ACTH (adrenocorticotropic hormone)
WHAT HORMONE?
MINERALOCORTICOIDS or GLUCOCORTICOIDS
GLUCOCORTICOIDS
ADRENAL CORTEX
CHEMICAL CLASS: STEROIDS
MAJOR ACTIONS: Promote reabsorption of Na+ and excretion of K+ in kidneys
REGULATED BY: changes in blood volume or blood pressure; K+ (potassium) or Na+ level in blood
WHAT HORMONE?
MINERALOCORTICOIDS or GLUCOCORTICOIDS
MINERALOCORTICOIDS
ADRENAL GLANDS
- inner neural tissue region;
produces catecholamines
(EPINEPHRINE & NOREPINEPHRINE)
CHEMICAL CLASS: AMINES
MAJOR ACTIONS: raise blood glucose level, increase rate of metabolism; constrict certain blood vessels
REGULATED BY: NERVOUS SYSTEM (sympathetic division)
MEDULLA
THE MAJOR ENDOCRINE ORGANS
- Pancreas is a mixed gland
1. Flattened organ that measures about 12.5-15 cm (5-6 in.) in length, located in the curve of the duodenum
- Chemical class: PROTEIN
- Little masses of hormone-producing
tissue scattered among the enzyme producing acinar tissue of the pancreas
PANCREATIC ISLETS
PANCREATIC ISLETS IS ALSO CALLED AS?
ISLET OF LANGERHANS
Cell Types in the Pancreatic Islets
- 17% of pancreatic islet cells & secrete GLUCAGON
CONTROL OF SECRETION: DECREASE blood level of glucose, exercise and mainly protein meals stimulate secretion; somatostatin and insulin inhibit secretion
PRINCIPAL ACTIONS: RAISE blood glucose by accelerating breakdown of glycogen into glucose
A. Alpha (A) cells
B. Beta (B) cells
C. Delta (D) cells
D. F cells
A. Alpha (A) cells
Cell Types in the Pancreatic Islets
- 70% of pancreatic islet cells & secrete INSULIN
CONTROL OF SECRETION: INCREASE blood level of glucose, acetylcholine (released by parasympathetic vagus nerve fibers), arginine, and leucine
PRINCIPAL ACTIONS: LOWERS blood glucose level by accelerating transport of glucose into cells, converting glucose into glycogen (glycogenesis) and decreasing glycolysis
A. Alpha (A) cells
B. Beta (B) cells
C. Delta (D) cells
D. F cells
B. Beta (B) cells
Cell Types in the Pancreatic Islets
- 7% of pancreatic islet cells & secrete SOMATOSTATIN
CONTROL OF SECRETION: pancreatic polypeptide inhibits secretion
PRINCIPAL ACTIONS: Inhibits secretion of insulin and glucagon; slows absorption of nutrients from GI tract
A. Alpha (A) cells
B. Beta (B) cells
C. Delta (D) cells
D. F cells
C. Delta (D) cells
Cell Types in the Pancreatic Islets
- 6% of pancreatic islet cells & secrete
PANCREATIC POLYPEPTIDE
CONTROL OF SECRETION: Meals containing protein, fasting,exercise, and acute hypoglycemia stimulate secretion; somatostatin and elevated blood glucose level inhibits secretion
PRINCIPAL ACTIONS: Inhibits somatostatin secretion, gallbladder contraction and secretion of pancreatic digestive enzymes.
A. Alpha (A) cells
B. Beta (B) cells
C. Delta (D) cells
D. F cells
D. F cells
THE MAJOR ENDOCRINE ORGANS
- A small, cone-shaped gland found hanging from the roof of the 3rd ventricle of the brain
- Secretes MELATONIN
Chemical class: AMINE
Contribute to the setting of the body’s biological clock
Peak levels are at night & lowest
levels is during daylight (noon)
May have other as yet
unsubstantiated functions
PINEAL GLAND
THE MAJOR ENDOCRINE ORGANS
- Located posterior to the sternum, between the lungs
- Largest in infants & children
- Produces THYMOSIN
Chemical class: PEPTIDE
Promotes maturation of some types of WBCs
May retard aging process
Important in developing the immune system
THYMUS GLAND
THE MAJOR ENDOCRINE ORGANS
- Produces sex cells and sex hormones that are identical to those produced by adrenal cortex cells
1. Ovaries
2. Testes
GONADS
Other Hormone-Producing Tissues & Organs
- Stimulates corpus luteum in ovary to continue production of estrogens & progesterone to maintain pregnancy
HUMAN CHORIONIC GONADOTROPIN (hCG)
Other Hormone-Producing Tissues & Organs
- Maintain pregnancy; help prepare mammary glands to secrete milk
ESTROGEN & PROGESTERONE
Other Hormone-Producing Tissues & Organs
- works cooperatively with estrogen & progesterone in preparing the breasts for lactation
HUMAN PLACENTAL LACTOGEN (hPL)
Other Hormone-Producing Tissues & Organs
- causes the mother’s pelvic ligaments & the public symphysis to relax & become more flexible, which eases the birth passage
RELAXIN
DISORDERS OF THE ENDOCRINE SYSTEM
- EXCESSIVE URINE OUTPUT due to HYPOSECRETION OF ADH
- Person is continually thirsty & drink huge amounts of water
DIABETES INSIPIDUS
PITUITARY DWARFISM
GIGANTISM
STERILITY
DIABETES INSIPIDUS
DISORDERS OF THE ENDOCRINE SYSTEM
- HYPOSECRETION OF GH during childhood slows bone growth, & the epiphyseal plates close before normal height is reached
DIABETES INSIPIDUS
PITUITARY DWARFISM
GIGANTISM
STERILITY
PITUITARY DWARFISM
DISORDERS OF THE ENDOCRINE SYSTEM
- Hypersecretion of GH during childhood, on abnormal increase in the length of long bones
- Acromegaly: hypersecretion of GH occurs after long-bone growth has ended
DIABETES INSIPIDUS
PITUITARY DWARFISM
GIGANTISM
STERILITY
GIGANTISM
DISORDERS OF THE ENDOCRINE SYSTEM
- Hyposecretion of FSH (follicle stimulating hormone) or LH (luteinizing hormone) in both males and females
DIABETES INSIPIDUS
PITUITARY DWARFISM
GIGANTISM
STERILITY
STERILITY
DISORDERS OF THE ENDOCRINE SYSTEM
- Enlargement of thyroid gland that results when the diet is deficient in iodine
GOITER
CRETINISM
MYXEDEMA
GRAVE’S DISEASE
GOITER
DISORDERS OF THE ENDOCRINE SYSTEM
- Congenital hypothyroidism
- Hyposecretion of thyroid hormones that is present at birth, causes severe mental retardation & stunted bone growth
GOITER
CRETINISM
MYXEDEMA
GRAVE’S DISEASE
CRETINISM
DISORDERS OF THE ENDOCRINE SYSTEM
- Hypothyroidism occurring in adults
- Occurs 5x more often in females
- Hallmark: EDEMA
GOITER
CRETINISM
MYXEDEMA
GRAVE’S DISEASE
MYXEDEMA
DISORDERS OF THE ENDOCRINE SYSTEM
- Most common form of hypermetabolism
- Autoimmune disorder in which the person produces antibodies that mimic the action of TSH
- Enlarged thyroid & exophthalmos (protruding eyes)
GOITER
CRETINISM
MYXEDEMA
GRAVE’S DISEASE
GRAVE’S DISEASE
DISORDERS OF THE ENDOCRINE SYSTEM
- Too little parathyroid hormone- leads to a deficiency of blood Ca2+, leading to twitches, spasms & tetany of skeletal muscle
HYPOTHYROIDISM
ADDISON’S DISEASE
HYPERALDOSTERONISM
CUSHING’S SYNDROME
HYPOTHYROIDISM
DISORDERS OF THE ENDOCRINE SYSTEM
- Hyposecretion of glucocorticoids &
aldosterone
- Majority of cases are autoimmune disorders, characterized by a peculiar bronze tone of skin
HYPOTHYROIDISM
ADDISON’S DISEASE
HYPERALDOSTERONISM
CUSHING’S SYNDROME
ADDISON’S DISEASE
DISORDERS OF THE ENDOCRINE SYSTEM
- Overproduction of the hormone aldosterone by adrenal glands
- Excessive water and sodium are retained, leading to high blood pressure & edema.
HYPOTHYROIDISM
ADDISON’S DISEASE
HYPERALDOSTERONISM
CUSHING’S SYNDROME
HYPERALDOSTERONISM
DISORDERS OF THE ENDOCRINE SYSTEM
- Hypersecretion of cortisol by the adrenal cortex
- Causes include a tumor of the adrenal gland that secretes cortisol, or a tumor elsewhere that secretes ACTH, which in turn stimulates excessive secretion of cortisol.
HYPOTHYROIDISM
ADDISON’S DISEASE
HYPERALDOSTERONISM
CUSHING’S SYNDROME
CUSHING’S SYNDROME
DISORDERS OF THE ENDOCRINE SYSTEM
- Hypersecretion of the sex hormones,
regardless of sex
- In females: beard develops & masculine pattern of body hair distribution occurs
MASCULINIZATION
DIABETES MELLITUS
HYPERINSULINISM
MASCULINIZATION
DISORDERS OF THE ENDOCRINE SYSTEM
- Inability to produce/use insulin
- Blood glucose level is high & glucose “spills” into the urine (glucosuria)
- Hallmarks: polyuria, polydipsia, & polyphagia
MASCULINIZATION
DIABETES MELLITUS
HYPERINSULINISM
DIABETES MELLITUS
DISORDERS OF THE ENDOCRINE SYSTEM
- Often results when a diabetic injects too
much insulin
- Main symptom: hypoglycemia
MASCULINIZATION
DIABETES MELLITUS
HYPERINSULINISM
HYPERINSULINISM
