ch 7 Flashcards
thyroid + parathyroid glands
isthmus
butterfly shaped and connects two lobes
thyroid gland location
between trachea and esophagus
thyroid gland anatomy
follicular cells surround colloid
- follicular cells are epithelial cells
- colloid is necessary bc thyroid hormones are protein based
- parafollicular cells js there
thyroid hormones
TRH, TSH, T3 (triiodothyronin- principal thyroid hormone), T4 (tetraiodthyronine), calcitonin (calcium regulation in the bloodstream and made by the parafollicular cells)
thyroid hormone synthesis and storage
needs 2 tyrosine and 3-4 iodine
T3 synthesis
tyrosines are iodinated to make one diiodotyrosine and one monoiodotyrosine
more potent
T4 synthesis
2 iodides added to each tyrosine within the thyroglobulin
- makes 2 diiodotyrosines
- thyroid peroxidase cleaves the tyrosines and combines the two
- both stays attached to the thyroglobulin until secretion
- makes hormones ahead of time
longer half-life
thyroid release and secretion
endocytosis: the cell takes the thyroglobulin w T3 and T4 attached and transported inside, they are released from the thyroglobulin by a lysosome
- specialized iodide channels on the surface to store in the colloid
endocrine regulation of the thyroid
hypothalamus > anterior pituitary > thyroid gland > bloodstream
stimulation for TRH
decrease in T3 or T4 levels in blood
- pulsatile secretion
- circadian rhythm and stress
functions of thyroid hormone
increases basal metabolic rate
important for growth in children and teens
- provides a “permissive” effect for other hormones (GH)
hyperthyroidism causes
causes: thyroid tumor or cancer
Graves’ disease: autoimmune disease of thyroid gland
hypothyroidism causes
Hashimoto’s disease: autoimmune disease of thyroid gland
malfunctioning thyroid gland
iodine deficiency
hyperthyroidism symptoms
symptoms: nervousness, high metabolic rate and weight loss, protruding eyeballs, goiter, rapid or irregular heartbeat, increased body temperature, muscle weakness
hyperthyroidism treatment
surgical removal of affected thyroid, radiotherapy with radioactive iodine, followed by thyroid hormone replacement therapy
hypothyroidism symptoms
fatigue and weakness, puffy face, low basal metabolic rate and weight gain, higher sensitivity to cold, thinning hair, goiter
neonatal hypothyroidism (cretinism) causes
iodine deficiency during pregnancy or the thyroid gland is absent, poorly developed, or malfunctioning
cretinism symptoms
puffy face, thick tongue protruding abdomen, umbilical hernia, muscle weakness
cretinism and hypothyroidism treatments
thyroid hormone replacement therapy, iodine deficiency and goiter (iodine supplementation), C cells- produce calcitonin (parafollicular cells)
calcitonin: function
hypercalcemia (more likely for women)
bones serve as major storage sights for calcium in the form of calcium phosphate crystals
bone deposition
osteoblasts secrete a matrix, which becomes hardened by deposits of calcium phosphate cystals
bone resorption
osteoclasts break down the calcium phosphate crystals
- results in an increased release of calcium into the blood
calcitonin reduces…
calcitonin reduces calcium uptake by the kidneys
- used as treatment to promote bone conservations
osteoporosis
abnormal thinning and weakening of bone
paget’s disease
abnormal remodeling of bone
parathyroid glands structure
two major types
- chief cells
- oxyphil cells
PTH function
stimulates osteoclast resorption in bone
adrenal cortex: adrenocorticosteroids
mineralocorticoids: aldosterone
glucocorticoids: cortisol
gonadocorticoids: sex hormones
mineralocorticoids
secretion is stimulated by angiotensin II
targets the kidneys
- regulates the balance of fluid and electrolytes in the blood
kidneys: function
nephron
- glomerulus within the bowman’s capsule
-tubules
aldosterone: secretion
secretion of aldosterone is stimulated by angiotensin II
- lowered blood volume (pressure)
- stimulation is indirect through angiotensin II
- low Na+ in the blood
- also indirect through angiotensin II
- low plasma Na+ and aldosterone
low cortisol symptoms
low glucose levels, fatigue, weight loss, reduced muscle mass, dizziness
glucocorticoids function
cortisol targets tissues throughout body
- regulate metabolism
- immune response
- body’s response and adaption to stress
regulation of immune response
immunosuppressive effects
lower white blood cells, lower antibody production, causes atrophy of tissues involved in the immune response
regulation of immune response
anti-inflammatory effect
blocks the release of proinflammatory chemicals
- eg histamines + prostaglandins
acute stress (glucocorticoids and the regulation of stress response)
a heightened state of tension that quickly passes
chronic stress (glucocorticoids and the regulation of stress response)
high levels of stress over a long period of time
physical stressors
starvation, major illness, surgery, physical trauma
psychological stressors (mental and emotional)
anything perceived by an individual as a threat to their survival, self-image, success, loss of a loved one, severe anxiety, or inability to solve a major problem
glucocorticoids (cortisol) and chronic stress
anxiety, weakened immune system, heart disease, nerve problems, high blood sugar
hypersecretion of glucocorticoids (cortisol) causes
tumor in the adrenal cortex, hypersecretion of ACTH, to prolonged glucocorticoid treatment (can lead to cushing’s syndrome)
hypersecretion of adrenocorticoids
cause: destruction of the adrenal cortex
inadequate levels of cortisol and/or aldosterone
(can lead to Addison’s Disease)
gonadocorticoids: synthesis
zona reticularis and adrenal androgens: produced in small amounts as weak androgens
males and gonadocorticoids
amount produced by the adrenal gland isn’t significant unless it is abnormally secreted in excess before puberty
excessive androgens in females
can cause virilization development of secondary sex characteristics more typical of males
- hirsutism: excessive hair growth that is dark and coarse
adrenal medulla: structure and function
composed of chromaffin cells
- postganglionic fiber
adrenal medulla secretes
85% epinephrine (adrenaline), 15% norepinephrine (noradrenaline), <1% dopamine
- epinephrine is adrenaline, norepinephrine is noradrenaline
fight or flight response
(cardiovascular)
increased heart rate, cardiac output, blood pressure
fight or flight (metabolic)
increased glycogenolysis becomes increased blood glucose
fight or flight (muscles)
dilation of bronchioles, relaxation of GI tract leads to decreased digestion, constriction of blood vessels in skin, dilation of blood vessels in skeletal muscle (blood is diverted to skeletal muscles)
glycogenolysis
conversion of glycogen to glucose
pancreas (structure and function)
beta cells more prevalent (alpha and beta work against each other)
glycogenesis
glucose converted to glycogen (complex)
!remember what a glucose monomer is!
glycergenesis
production of glycerol from glucose
lipogensis
lipid= glycerol (simple)+fatty acids(simple)= triglyceride (complex)
triglyceride
glycerol + fatty acids
diabetes mellitus symptoms
hyperglycemia, increased urination, increased thirst, hunger, fatigue, infections, weight loss, pain/tingling, blurred vision, blindness, kidney failure, heart disease, stroke, loss of toes, feet, legs
type 1 diabetes cause
genetics
type 2 diabetes causes
body can’t use insulin properly, overweight, family history, physically inactive, over 45
how to prevent type 2
eat healthy, lose weight, exercise regularly
hypoglycemia causes
incorrect dosage of insulin, dangerously low
hypoglycemia symptoms
shaky, sweaty, dizzy, confusion, hungry, weak, or tired
pancreas
exocrine and endocrine function
- secretin and small intestine (Bayliss and Starling)
pancreas beta cells
make insulin
pancreas alpha cells
make glucagon
3 sites of storage for glycogen
liver, muscles, adipose tissue
pancreas releases insulin
decreased glucose in blood
pancreas releases glucagon
increased glucose in blood
