A&P Test 2 Lecture 9 Flashcards
Thyroid Follicles
Create thyroid hormones; consisted of a proteinaceous secretory substance called colloid surrounded by follicular cells.
Parafollicular Cells
are cells found between the numerous thyroid follicles.
Thyroid Hormones
T4 and T3
- stimulate increases in the basal metabolic rate of the animal.
- stimulate increases in availability of substances for oxidative metabolism.
- stimulate increase in cardiac output to meet increased )2 demand.
- stimulate reactivity of the nervous system
- in infants: maturation of nervous system.
Basal Metabolic Rate (BMR)
resting rate of calorie expenditure by the body.
Thyroid-stimulating hormone (TSH)
stimulates the follicular cells in the thyroid gland to release T3 and T4
Thyrotopin- releasing Hormone (TRH)
Released from hypothalamus to maintain constant thyroid hormone level.
Goiter
and enlarged thyroid gland
Calcitriol
made from vitamin D. stimulates absorption of dietary Ca^+2 by the intestine.
Parathyroid hormone
increases plasma Ca+2 and decreases PO4^-3
Parathyroid Gland
four small lobes of glandular tissue embedded in the dorsal side of the thyroid gland.
Calcitonin (CT)
lowers plasma Ca^+2; controls Ca^+2 in the ECF of non-pregnant mammals, major regulator of Ca^+2 in lower vertebrates.
Rickets
Vitamin D deficiency do to lack of exposure to the sun and lack of vitamin D in the diet.
Vitamin D
A deficiency can lead to bone softening which results in bow-legged and in severe cases can cause seizures.
Cretinism
congenital hypothyroidism results in severely stunted physical and mental growth