Endocrine A&P Flashcards
What are the major glands of the endocrine system?
Hypothalamus, Pituitary, Thyroid, Parathyroid, Pancreas, Adrenals, Ovaries/Testes, Pineal Gland
What is a specific cell with a specific receptor that will respond to specific hormones?
Target cell
How many receptors does a target have for a particular hormone?
200-100,000
Hormones are either ___-soluble or ____-soluble
Lipid-soluble or water soluble
How do lipid soluble hormones affect cell function?
Altering gene expression, receptor is in the nucleus
How do water soluble hormones affect cell function?
Activating plasma membrane receptor
What gland is known as “master switchboard” and acts as a major link between the endocrine and nervous system?
Hypothalamus
What is known as “master gland of the body” because it regulates the activity of the endocrine glands?
Pituitary gland
What attaches the pituitary gland to the hypothalamus?
Infundibulum
Within the infundibulum, what blood vessels transport hormones in the hypothalamus to the anterior pituitary?
Hypophyseal portal veins
What are hormones secreted by the hypothalamus?
Gonadotropin-releasing
Growth hormone-releasing
Growth hormone-inhibiting
Thyroid-releasing hormone
Prolactin-releasing hormone
Prolactin-inhibiting hormone
Corticotropin-releasing hormone
What does gonadotropin-releasing hormone stimulate?
FSH and LH
What does growth hormone-releasing hormone stimulate?
HGH and IGF
What does growth hormone-inhibiting hormone inhibit?
HGH and IGF
What does thyroid-releasing hormone stimulate?
TSH
What does prolactin-releasing hormone stimulate?
PR
What does prolactin-inhibiting hormone inhibit?
PR
What does corticotropin-releasing hormone stimulate?
ACTH
What are the 2 lobes of the pituitary gland?
Anterior and posterior pituitary gland
What is a hormone that stimulates an endocrine gland to grow and secrete its hormones?
Tropic hormones
What are the tropic hormones of the anterior pituitary gland?
Human Growth Hormone (hGH)
Thyroid stimulating hormone (TSH)
Follicle Stimulating hormone (FSH)
Luteinizing Hormone (LH)
Prolactin (PRL)
Adrenocorticotropic hormone (ACTH)
Melanocyte-stimulating hormone (MSH)
What hormone promotes synthesis and secretion of Insulinlike Growth Factors (IGFs)
Human Growth Hormone (hGH)
What proteins are secreted by cells in the liver, skeletal muscles, cartilage, bones and other tissues in response to hGH?
Insulinlike Growth Factors (IGF)
What feedback loop maintains hGH concentration in the blood?
Negative feedback
What 2 hypothalamic hormones control secretion of hGH?
Growth hormone-releasing hormone (GNRH)
Growth hormone-inhibiting hormone (GHIH)
What is the difference between GNRH and GHIH?
GHRH- low blood glucose
GHIH- above normal blood glucose
What hormone stimulates synthesis and secretion of thyroid hormones by the thyroid gland?
Thyroid-stimulating hormone (TSH)
What controls TSH secretion from the hypothalamus?
Thyrotropin-releasing hormone (TRH)
What initiates development of ovarian follicles and stimulates follicular cells to excrete estrogen in females?
Follicle-stimulating hormone (FSH)
What stimulates sperm production in testes and is controlled by GnRH in the hypothalamus?
Follicle-stimulating hormone (FSH)
What triggers ovulation, stimulates formation of the corpus luteum in the ovary and stimulates follicular cells to secrete estrogen?
Luteinizing hormone (LH)
What stimulates the testes to secrete testosterone and is controlled by GnRH from the hypothalamus?
Luteinizing hormone (LH)
What initiates and maintains milk production of the mammary glands?
Prolactin (PRL)
What suppresses release of prolactin?
Prolactin-inhibiting hormone (PIH)
What hormone during pregnancy stimulates the secretion of prolactin due to high levels of estrogen?
Prolactin-releasing hormone (PRH)
What controls production and secretion of glucocorticoids by cortex of the adrenal gland?
Adrenocorticotropic Hormone (ACTH)
What hormone from the hypothalamus stimulates secretion of (ACTH)?
Corticotropin-releasing hormone
What hormone is very little in humans and excessive amounts can cause darkening of the skin?
Melanocyte-stimulating hormone (MSH)
What portion of the pituitary contains axons and axon terminals of neurosecretory cells whose cell bodies are in the hypothalamus?
Posterior pituitary
What does the posterior pituitary do in regards to hormones?
Does not synthesize hormones, doe store and release oxytocin and antidiuretic hormone (ADH)
How does oxytocin affect the uterus?
Does not synthesize hormones, does store and release oxytocin and antidiuretic hormone (ADH)
How does oxytocin affect the uterus?
Released in large quantities just prior to childbirth to enhance contraction of smooth muscle cells in the wall of the uterus
How does oxytocin affect the breast?
Stimulates milk ejection from the mammary glands in response to suckling infant
What hormone decreases urine output, decreases water loss through sweating, causes kidneys to retain more water and increase blood pressure?
Antidiuretic hormone (ADH)
What happens to a person if they lack ADH?
Increase urine output from 1-2liters per day to 20liters
Which gland’s function is to run the basal metabolic rate (BMR)?
Thyroid gland
What is basal metabolic rate (BMR)?
Rate at which body uses energy while at rest to keep vital functions going such as breathing, keeping the heart beating and keeping the body warm
What are the spherical sacs that make up most of the gland called?
Thyroid follicles
What are the 2 thyroid hormones thyroid follicles produce?
Thyroxine (T4)
Triiodothyronine (T3)
What is the most abundant thyroid hormone?
T4
What does T4 convert into after entering the cell?
T3
What is produced by the parafollicular cells of the thyroid gland?
Calcitonin (CT)
Calcitonin decreases level of calcium in the body by inhibiting which cell that breaks down bone?
Osteoclasts
Calcitonin is produced by which cells of the thyroid gland?
Parafollicular cells
What are small round masses of glandular tissue that are partially embedded in the posterior surface of the thyroid?
Parathyroid glands
What cells are within the parathyroid gland that release parathyroid hormone (PTH)?
Chief cells
What hormone is a major regulator of levels of calcium, magnesium and phosphate of ions in the blood?
Parathyroid hormone (PTH)
What is the effect of PTH on osteoclasts?
Increases activity which break down bone and extracellular matrix and release calcium and phosphate into the blood
How does PTH effect the kidneys?
Slows rate at which calcium and magnesium are lost from blood into urine
Increases loss of phosphate from blood to urine
Promotes formation of hormone ccalcitrol which increases rate of calcium, magnesium and phosphate absorption form food into blood
What level of PTH causes bone pain, kidney stones, headaches and abdominal pain?
Elevated levels of PTH
What level of PTH can cause carpopedal spasms, abdominal pain and muscle cramps
Low levels of PTH
What is a flattened organ located in the curve of the duodenum and the first part of the small intestine?
Pancreas
The pancreas has functions of which systems?
Endocrine and exocrine functions
Which portion of the pancreas has the endocrine part?
Islets of Langerhans
What hormone do alpha cells of the pancreas secrete?
Glucagon
Glucagon from alpha cells is stimulated by which portion of ANS?
Sympathetic division of ANS
What hormone do beta cells of the pancreas secrete?
Insulin
Insulin from beta cells is stimulated by which portion of the ANS?
Parasympathetic division of ANS
What hormone increases blood glucose level when it falls below normal?
Glucagon
What hormone lowers blood glucose when it is too high?
Insulin
What kind of feedback controls secretion of glucagon and insulin?
Negative feedback
What are the 2 glands lying atop each kidney?
Adrenal glands
What are the 2 regions of the adrenal glands?
Adrenal Cortex
Adrenal Medulla
What are the 3 zones of the adrenal cortex?
Outer zone (Zona glomerulosa)
Middle zone (Zone fasciculata)
Inner zone (Zona reticularis)
What hormone does the outer zone release?
Aldosterone
What hormone does the middle zone release?
Cortisol
What hormone does the inner zone release?
Androgens (male and female sex hormones)
What hormones does the Adrenal Medulla secrete?
Epinephrine and Norepinephrine
What is a major mineral corticoid?
Aldosterone
What ions are regulated by aldosterone?
Sodium (Na+) and Potassium (K+)
What initiates the renin-angiotensin-aldosterone pathway?
Dehydration, Na+ deficiency, hemorrhage, decrease BP and blood volume
Lowered blood pressure stimulates the secretion of renin, which promotes the blood to form which hormone?
Angiotensin I
As angiotensin I flows through the body, which enzyme converts angiotensin I into angiotensin II?
Angiotensin converting enzyme (ACE)
How does angiotensin II stimulate the adrenal cortex?
Secretes aldosterone
What effect does aldosterone have on the kidneys?
Promotes return of Na+ and water to the blood
What is the most abundant glucocorticoid?
Cortisol
Cortisol has what kind of effects?
Protein breakdown
Glucose formation
Anti-inflammatory effects
Depression of immune response
What occurs when cortisol is low?
Hypothalamus secretes corticotropin-releasing hormone (CRH) to the anterior pituitary.
Anterior pituitary then secretes adrenocorticotropic hormone (ACTH)
ACTH stimulates cells of the adrenal cortex to
What is the effect of androgens from the adrenal cortex in males?
Small amounts of androgens are secreted by males. After puberty, androgens are released in much greater quantities by the testes, thus the amount from the adrenal cortex is insignificant
What is the effect of androgens from the adrenal cortex in females?
Contribute to libido and converted into estrogen. After menopause, all female estrogen is from conversions of androgen
What is the effect of androgens from the adrenal gland in both sexes?
Stimulate axillary and pubic hair in boys and girls and contribute to growth spurt before puberty. Stimulated by the secretion of ACTH
What hormones does the adrenal medulla secrete in stressful situations?
Epinephrine and norepinephrine
How does epinephrine and norepinephrine affect the heart?
Increases heart rate, contraction which increase output and increases blood pressure
What hormones augment the fight or flight response?
Epinephrine and norepinephrine
What are the organs that produce gametes?
Gonads
What are the female sex hormones produced by the ovaries?
Estrogen and progesterone
What hormones regulate menstrual cycle, maintain pregnancy, prepare mammary glands for lactation and maintain the feminine body shape?
FSH, LH, Estrogen and progesterone
What hormone does the ovaries produce that inhibits the secretion of FSH?
Inhibin
During pregnancy, what hormone is produced by the ovaries and placenta increases the flexibility of the pubic symphysis and dilates the cervix during labor?
Relaxin
What hormone does the testes produce?
Testosterone
Sertoli cells in the testes produce which hormone?
Inhibin
What is a small endocrine gland attached to the roof of the third ventricle of the brain at the midline?
Pineal gland
What hormone is secreted by the pineal gland that contributes to circadian rhythm?
Melatonin
What hormone decreases causing muscle atrophy as we age?
Human growth hormone
What hormone decreases causing decreased metabolic rate, increased body fat and hypothyroidism as we age?
T3, T4, calcitonin
What hormone increases causing osteoporosis as we age?
Parathyroid hormone
What hormone is released more slowly as we age causing blood glucose to increase faster?
Insulin
What hormone decreases as females age and no longer causes responds to gonadotropin which leads to osteoporosis, hyperlipidemia and atherosclerosis?
Estrogen
What is a stimulus that produces a stress response?
Stressor
What is a sequence of bodily changes that can progress through stages?
Stress response
What are the stages of stress response?
Fight or flight
Slower resistance reaction
Exhaustion
Which stage of stress response quickly mobilizes the body’s resources for immediate physical activity?
First stage: Fight or flight
During fight or flight response, what is brought to the organs that are most active in warding off danger?
Glucose and oxygen
How does the kidney respond to the fight or flight response?
Reduction of blood flow to the kidneys, promotes the release of rennin
What initiates the fight or flight response?
Nerve impulses