Metabolic Rate & Temperature Regulation

Week 7: Tuesday, October 7th: Review & Midterm Exam 1; Thursday, October 9th: Endocrine Glands & Dysfunction: The Thyroid Gland (cont.); Week 9: Tuesday, October 21st: Metabolic Rate & Temperature Regulation (cont.); Thursday, October 23rd: Growth

the following are _______ effects of the thyroid gland:

1. metabolism of carbohydrates, lipids, and proteins

2. basal metabolic rate (how quickly our body metabolized energy at rest/baseline)

3. temperature

4. growth and nature

physiological

effector organs of the hypothalamus, which all have thyroid receptors, are (5 in total):

bones, the brain, nerves, the heart, and body cells

pressure on the eyes that causes bulging, and excessive thyroid hormone in the blood describes _______

exophthalmos

_______ is also known as hypothyroidism, and has the following characteristics:

1. . metabolic dysregulation

2. an autoimmune disease

3. High basal metabolic rate (BMR)

4. Increased sweating

5. Weight loss

Graves’s disease

_______ is also known as hyperthyroidism, and has the following characteristics:

1. Still causes goiter

2. metabolic dysregulation

3. low basal metabolic rate (BMR)

4. Decreased sweating

5. Weight gain

Hashimoto’s disease

in 1814, Gay-Lussac discovered that _______ deficiency caused goiter, so he fed those with the disease seaweed and marine products

iodine (I2)

in 1895, Kocher found high amounts of iodine (I2) in the _______

thyroid gland

in 1918, Kendall found and named _______, which has four iodine atoms bound to a tyrosine

thyroxine/tetraiodothyronine (T4)

in 1952, Gross and Pitt-Rivers found and named _______, a more active form of thyroid hormones that has three iodine atoms bound to a tyrosine

triiodothyronine (T3)

_______ can remove iodine form tetraiodothyronine (T4) to create triiodothyronine (T3)

Deionodases

the thyrid gland developed from the embyro’s _______

digestive tube

true or false: if the thyroid gland weighs more than 20g, this indicates a thyroid disease

true

the thyriod gland communicates and delivers hormones via

large sympathetic and parasympathetic nerves, and blood and lymph 

_______ are special cuboidal/columnar epithelial cells in the thyroid gland that make T3 and T4

thryoid follicles

the lumen around each thyroid follice cell is filled with a glycoprotein colloid called _______

thyrogobulin (TG)

_______ produce calcitonin, which is involved in calcium homeostasis

parafollicular c cells

describe the process of thyroid hormome secretion, starting with iodide entering the cell:

1. iodide (I^-) enters the cell bound to _______

2. The cell charge changes once I^- enters, _______ out, and _______ in

3. I^- is oxidized by _______ to become I²

4. _______ attaches I² to Thyroglobulin (TG)

5. triiodothyronine (T3) and tetraiodothyronine (T4) are produced from _______ and _______

6. _______ binds to these cells to release triiodothyronine (T3) and tetraiodothyronine (T4)

1. Na+

2. Na+, K+

3. thyrooxidase (TO)

4. thyroid peroxidase (TPO)

5. diiodotyrosine (DIT), monoiodotyrosine (MIT)

6. thyroid-stimulating hormone (TSH)

_______ stimulates T3 and T4 production

TSH

T3 and T4 are lipid soluble, but they reqiure _______ receptors to enter cells and control when they can enter

transmembrane

_______ is the thyroid hormone that can enter the nucleus because its the actice form

T3

when hormones levels are too high, T3 will turn off the anterior pituitary to stop TSH, which is a _______ negative feedback

direct

when hormones levels are too high, T3 will turn off the hypothalamus to stop TRH, which is an _______ negative feedback

indirect

TRHR (TRH receptor), which is located on anterior pituitary cells, is what type of G-protein receptor?

G alpha q

T4 is converted into T3, which does what to the TRHR on anterior pituitary cels

slows down/downregulates

during fetal development, nervous system maturation depends on _______ and _______

T3 and T4

In adults, thyroid hormones increase sympathetic activity by upregulating _______ receptors

adrenergic

Thyroid hormones increase heart rate and contractility by affecting _______ channels

ion

T3 acts permissively with _______ to promote bone formation.

growth hormone

T3 determines when bone growth _______ (ends).

stops

Thyroid hormones increase oxygen consumption and heat production by increasing _______ use.

ATP

Uncoupling proteins in mitochondria produce _______ instead of ATP.

heat

Hyperthyroidism causes muscle _______ due to excess protein breakdown.

wasting

Conversion of T4 to T3 in the pituitary provides _______ feedback to reduce TSH release.

negative