Download Hormones

Hormones
1. Production and Role of Hormones
a. Hormones act as chemical signals
i. Each has a specific shape that is recognized by target cells
ii. Binding to receptor on or in target cell causes chemical reactions within the cell
b. Hormone control
i. hypothalamus – area of the brain secretes hormones that cause the
ii. pituitary gland to secrete other hormones that cause other parts of the endocrine
system to secrete hormones.
1. TSH – secreted by the pituitary gland – controls Thyroid
a. Thyroxine is a hormone produced by thyroid
i. Controls: vertebrate development and maturation, blood
pressure, heart rate, muscle tone, digestion and
reproduction
ii. Deficiency: weight gain, intolerance to cold, lethargy or if
iodine is lacking: goiter
iii. Too much: loss of weight, high body temp, profuse
sweating, irritiability
2. ACTH – secreted by the pituitary gland – controls adrenal glands
a. Adrenaline (epinephrine) is hormone produce by adrenal glands
i. Secreted in response to positive or negative stress:
responsible for quickening heart rate, goose bumps, etc.
ii. Increases basal metabolic rate, and available energy
sources (rate of glocygen breakdown, release of glucose
from liver, release of fatty acid from fat cells)
iii. Affects cardiovascular and respiratory system
iv. Increases oxygen in the blood
v. Causes blood to flow away from skin, digestive organs, and
kidneys and to the heart, brain and skeletal muscles.
3. FSH/LH – secreted by the pituitary gland – controls gonads
a. 3 kinds of steroid hormones released by gonads
i. Androgens (testosterone)
1. made in testes
2. responsible for development of male reproductive
system
ii. Estrogens (estradiol)
1. Made in ovaries
2. responsible for development of female
reproductive system
iii. Progestins (progesterone)
1. Made in ovaries
2. responsible for preparation and maintenance of
uterus
b. Estrogen, Progesterone, FSH and LH are responsible for controlling
the female menstrual cycle.
i. The secretion of FSH and LH can be controlled by the
amount of estrogen and progesterone present
ii. Without FSH and LH, ovulation (release of egg from ovary)
cannot occur.
iii. This is how oral contraceptives work – pill is mixture of
estrogen and progesterone that work to prevent release of
FSH and LH from pituitary gland and thereby prevent
ovulation. No ovulation = no egg in uterus = no baby.
iii. Insulin
1. is a hormone that is not controlled by the pituitary gland but by the
amount of glucose in the blood
2. Secreted by the Pancreas
3. Regulates the concentration of glucose in blood
a. Ideal point is 90 mg/100 mL
b. If too high: insulin is released causing
i. Cells to take up glucose
ii. Reduction in glycogen breakdown in liver
iii. Inhibition of conversion of amino acids and fatty acids to
sugar
c. If too low: glucagon is released causing the opposite reactions
4. Deficiency of insulin causes Diabetes
a. Type I: childhood onset, need shots
b. Type II: adulthood onset, need to control through diet and
exercise
2. Outline the use and abuse of steroids
a. Use:
i. Treatment of wasting illness
ii. To regain muscle tissue
iii. Treatment of eczema
b. Abuse:
i. Increase muscle mass to enhance performance
ii. Increase strength