Chapter 17 Flashcards
Differences between nervous and endocrine systems?
E - slower, widespread effects, response persists
N - faster, targets specific organs, adapts quickly to repeated stimulus
What does the endocrine system use as a messenger?
Hormones
What does the nervous system use as a messenger?
Neurotransmitters
Where do hormones travel?
Through blood
What are the glands of the endocrine system?
Pineal gland, pituitary gland, pancreas, parathyroid gland, thyroid gland, thymus, ovaries/testes, adrenal gland, hypothalamus
Review a pineal gland slide
Done
Review a hypothalamus slide
Done
Review a pituitary gland slide
Done
Review a thyroid gland slide
Done
Review a thymus slide
Done
Review an adrenal gland slide
Done
Review a pancreas slide
Done
Review a parathyroid gland slide
Done
Review an ovary slide
Done
Review a testes slide
Done
What are the 3 chemical classes?
Steroids, peptides and glycoproteins, and monoamines
What chemicals are fat soluble?
Steroids
What chemicals are water soluble?
Peptides and glycoproteins and monoamines
How do fat soluble chemicals enter the cell?
Through membrane, they just head to the nucleus
How do water soluble chemicals enter the cell?
They don’t, they activate a second-messenger system
Traits of hormone receptors?
Specificity and saturation
Main usage of hormones?
Negative feedback system
What secretes steroids?
Gonads and adrenal glands
What secretes peptides and glycoproteins?
Pituitary gland and hypothalamus
What secretes monoamines?
Adrenal, pineal, and thyroid glands
What do steroid hormones do upon entering the cell?
Enter the nucleus to activate receptors which trigger transcription of translation for forming new proteins
How do peptides and glycoproteins act on the cell?
Bind to receptors in membrane, activate G proteins, activating other enzymes, activating cAMP, a second-messenger
What is specificity?
Specific receptor for each hormone
What is saturation?
Hormones only stimulate cells that have receptors for them
Interactive effects between hormones?
Synergistic, permissive, and antagonistic
What are usually stimuli for hormone release?
Hormonal, humoral (electrolytes), and neural
4 ways the body communicates from cell to cell?
Gap junctions, neurotransmitters, paracrines (local hormones), and hormoens
How do exocrine glands secrete?
Through duct onto epithelial surface
How do endocrine glands secrete?
Into blood stream
What releases ADH?
The posterior pituitary gland
What produces ADH?
Hypothalamus
What does ADH do?
Cause vasoconstriction and cause water to be reabsorbed into kidney capillaries
What does oxytocin do?
Produce uterine contractions and milk let-down
What does growth hormone do?
Stimulate protein synthesis in bone, cartilage, and muscle, and promote fat metabolism, and increase rate of amino acid reuptake by cells
What produces calcitonin?
Thyroid gland
What does calcitonin do?
Lower blood calcium
What do the pancreatic islets produce?
Insulin and glucagon
What produces melatonin?
The pineal gland
What happens when there is an increase in growth hormone during growing years?
Gigantism
What produces atrial natriuretic hormone (ANP)?
The heart
What produces erythropoietin (EPO)?
The kidney
What produces epinephrine?
The adrenal medulla
What produces thyroxine?
The thyroid
What produces aldosterone?
The adrenal cortex
What kind of effects do endocrine and exocrine glands have?
Endocrine - intracellular
Exocrine - extracellular
What are fenestrated capillaries?
Blood vessels in endocrine glands with large pores in their walls for easier uptake of matter from gland tissue
What makes up the endocrine system?
Glands, tissues, and cells that secrete hormones
What chemicals are fat soluble?
Steroids
What chemicals are water soluble?
Monoamines and peptides and glycoproteins
What secretes steroids?
Gonads and adrenal glands
What secretes peptides and glycoproteins?
Pituitary gland and hypothalamus
What secretes monoamines?
Adrenal, pineal, and thyroid glands
What are steroids derived from?
Cholesterol
Where are peptides and glycoproteins derived from?
Made from a chain of amino acids
What hormone groups are hydrophilic?
Peptides and glycoproteins and monoamines
Where are receptors located and what are they made of?
Protein or glycoprotein molecules on the plasma membrane, in the cytoplasm, or in the nucleus
What do receptor-hormone interactions exhibit?
Specificity and saturation
What is specificity?
Each hormone has its own specific receptor
What is saturation?
Hormones only stimulate cells that have receptors for them
What are the hormone interaction effects?
Synergistic, permissive, and antagonistic
What is up-regulation?
A permissive effect where the number of receptors (and therefore sensitivity to hormones) is increased
What is down-regulation?
A permissive effect where the number of receptors (and therefore sensitivity to hormones) is decreased
How is pituitary secretion controlled?
Negative and positive feedback
What is negative feedback?
Increased target organ hormone levels will inhibit release of hormones
What is the adenohypophysis?
The anterior 3/4 of the pituitary gland
What is the neurohypophysis?
Posterior 1/4 of the pituitary gland
How is the anterior pituitary connected to the hypothalamus?
The hypophyseal portal system
What makes up the hypophyseal portal system?
Primary capillaries in the hypothalamus connect to secondary capillaries in the anterior pituitary by portal venules
What is the neurohypophysis made of?
Nerve tissue
What is the hypothalamo-hypophyseal tract?
In the posterior pituitary, how the posterior pituitary hormones reach the posterior lobe
Special trait of the posterior pituitary gland?
It doesn’t synthesize hormones, it just stores them until prompted to release them
Which pituitary gland is dark?
The anterior
Which pituitary gland is light?
The posterior
What are the anterior lobe hormones?
Follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, prolactin, growth hormone
What are the hypothalamic hormones?
Gonadotropin-releasing hormone, thyrotropin-releasing hormone, corticotropin-releasing hormone, prolactin-inhibiting hormone, growth hormone-releasing hormone, and somatostatin
What does thyroid-stimulating hormone do?
Stimulate secretion of thyroid hormone
What does follicle-stimulating hormone do?
Stimulate secretion of ovarian sex hormones, development of ovarian follicles, and sperm production
What does luteinizing hormone do?
Stimulate ovulation, stimulate progesterone, and stimulate testes to secrete testosterone
What does adrenocorticotropic hormone do?
Stimulate adrenal cortex to secrete glucocorticoids
What does prolactin do?
Stimulate mammary glands to synthesize milk, and enhance secretion of testosterone by testes
What does growth hormone do?
Stimulate tissue growth in bone, cartilage, muscle, and fat
What does antidiuretic hormone do?
Increase water retention, reduce urine volume, prevent dehydration, and stimulate vasoconstriction
What happens when you drink alcohol?
Antidiuretic hormone secretion is inhibited, so you have to pee a lot
What is diabetes insipidus?
A disorder caused by the hyposecretion of ADH
What does oxytocin do?
Stimulate labor contractions, stimulate flow of breast milk, and get released during arousal and orgasm to propel and move semen up uterus
What is the most versatile hormone?
Growth hormone
What specific organ does growth hormone most affect?
The liver
Effects of insulin-like growth factors?
Increased protein synthesis, increased lipid metabolism, and electrolyte balancing
How can you increase natural GH production?
Vigorous exercise
What is aromegaly?
Caused by hypersecretion of GH, thickening of bones and soft tissue in adults
What is gigantism caused by?
Increase of GH during childhood and adolescence
What is pituitary dwarfism caused by?
Hyposecretion of GH
Where is the pineal gland?
Attached to the roof of the third ventricle in the brain
What does the pineal gland do?
Synthesize melatonin on 24-hour circadian rhythm
What systems does the thymus have a role in?
Endocrine, lymphatic, and immune
What does the thymus secrete?
Thymopoietin, thymosin, and thymulin. They stimulate development of lympatic organs and T lymphocytes
What are follicular cells?
Cuboidal epithelium cells in the thyroid gland which secrete T4 and T3
What are components of the thyroid gland?
Follicular cells, C (parafollicular) cells, and follicles
What do follicular cells do?
Increase metaboloic rate, heat production, appetite, alertness, and quicken reflexes
What do parafollicular cells do?
Stimulate osteoblast activity and bone formation
What is a goiter?
Any pathological enlargement of the thyroid gland
What is an endemic goiter?
Caused by dietary iodine deficiency, where there is no thyroid hormone to give feedback so thyroid stimulating hormone stimulates hypertrophy
What is a toxic goiter?
When autoantibodies mimic the effect of TSH on the thyroid, causing hypersecretion
What is myxedema?
Adult hypothyroidism
What is congenital hypothyroidism?
Hyposecretion present from birth
How do you treat thyroid conditions?
Oral thyroid hormone
What does parathyroid hormone do?
Increase blood calcium levels by increasing bone resorption
What is hyperparathyroidism?
Caused by a parathyroid tumor, there is hypersecretion and the bones become soft, fragile, and deformed
What is hypoparathyroidism?
Caused by a surgical excision during thyroid surgery, can cause fatal tetany in a few days due to rapid decline in blood calcium level
Where are the adrenal glands?
Atop each kidney
Layers of adrenal cortex from outermost to innermost?
Zona glomerulosa, zona fasciculata, zona reticularis
What is aldosterone?
Secreted by the adrenal cortex, it stimulates salt and water retention and potassium excretion, maintaining blood volume and pressure
What is cortisol?
Secreted by the adrenal cortex, it stimulates fat and protein catabolism
WHat is gluconeogenesis?
Forming glucose from amino and fatty acids and releasing it into the blood
What does cortisol help with?
Adapting to stress and repairing tissues. Anti-inflammatory effect
What do androgens do?
Set libido, and have a role in prenatal male development
What does estradiol do?
There’s only a little, but it helps you sustain bone mass after menopause. Fat converts androgens into estrogen
What is Cushing syndrome?
Excess cortisol secretion causing hypertension, hyperglycemia, weakness, and edema. As well as a moon face and buffalo hump
What is Addison’s disease?
Hyposecretion of cortisol, causing fatigue, hypoglycemia, weakness, and weight loss
What is adrenogenital syndrome?
Adrenal androgen hypersecretion, causing masculinized genitalia in women and increased body hair, deeper voice, and beard growth
What is special about the adrenal medulla?
It acts as both an endocrine gland and a sympathetic ganglion
Make-up of the adrenal medulla?
Innervated by sympathetic preganglionic fibers, and consists of sympathetic postganglionic neurons
What does the adrenal medulla secrete?
Epinephrine and norepinephrine, and a trace of dopamine
What are catecholamines?
Epinephrine and norepinephrine
Functions of the adrenal medulla?
Increases alertness and blood pressure, heart rate, blood flow to muscles, pulmonary airflow, and metabolic rate. Decreases digestion and urine production
What do glycogenolysis and gluconeogenesis do?
Boost glucose levels
What is glucose-sparing effect?
An effect that inhibits insulin secretion, so muscles use fatty acids, leaving glucose for the brain
What is the pancreas?
An exocrine digestive gland with endocrine cell clusters called pancreatic islets
What is glucagon?
Secreted by alpha cells of the pancreatic islets, it stimulates glucose production and release into the blood
What is insulin?
Secreted by beta cells of the pancreatic islets, it stimulates cells to absorb nutrients and lower blood glucose levels
What is diabetes mellitus?
Most common form of diabetes, disruption of metabolism due to hyposecretion or inaction of insulin
What is type 1 diabetes mellitus, or IDDM?
Rarer, complete lack of insulin requiring injections and monitoring of glucose levels. Genetic or occurs from viruses
What is type 2 diabetes mellitus, or NIDDM?
More common, insulin resistance means target cells don’t respond to insulin. Caused by obesity, age, and race
Symptoms of diabetes mellitus?
Elevated blood glucose, polyuria (excessive urine), glucose in urine (glycosuria) and ketones in urine (ketonuria), polydipsia (thirst), and polyphagia (hunger)
Exocrine product of the gonads?
Ovum and sperm, which are whole cells
Endocrine product of the gonads?
Gonadal hormones, mostly steroids
What do the testes do?
Stimulate testosterone, which stimulates development of male reproductive system and sex drive and sperm production
What do the ovaries do?
Lined by granulosa which produce estrogen (or estradiol), which develops female reproductive system and physique, regulates menstrual cycle, sustains pregnancy, and prepares mammary glands for lactation
Endocrine functions of skin?
Keratinocytes turn cholesterol-like steroid into cholecalciferol (precursor to vitamin D.) using UV rays
Endocrine functions of liver?
Converts cholecalciferol into calcidiol, secretes angiotensinogen, and secretes 15% of erythopoietin
Endocrine functions of kidneys?
Convert calcidiol to calcitriol, secrete renin to turn angiotensinogen into angiotensin I, and produce 85% of erythropoietin
What does erythropoietin do?
Stimulates bone marrow to produce RBCs
Endocrine functions of the heart?
Cardiac muscle secretes atrial natriuretic peptides (ANP) in response to blood pressure increase
What does ANP do?
Decrease blood volume and pressure by increasing sodium and water output by kidneys
Endocrine functions of adipose tissue?
Release leptin after meals, which regulates the balance between food intake and energy expenditure
