Bio 104, 5/21/96
Bio 104 5/21/96
These notes have not been reviewed by Dr. Barstow
Hormones:
- steroids
- peptides
- proteins
- modified amino acids
- these effect target cells
2 types of action: (See figure 37.4 in Friday's notes)
- Steroids are soluble in fats; so, they go straight
into the cell. Receptor proteins combine with steroids
and both go into the nucleus and alter protein
synthesis.
- Peptide hormones are not soluble in fat, but have
receptor cells in the cell membrane. (See figure 37.6)
The "second messenger" alters cell function by turning
on other systems which change glycogen to glucose.
Actions of Hormones See figures 37.7 and 37.8
Consult table 37.2 on page 708
The human neuroendocrine system. Figure 37.7
The major hormones secreted by the pituitary gland. Figure 37.8
Posterior pituitary has 2 secretions:
- ADH
- used for the retention of water
- Oxytocin
- contraction of the uterus
- induces the mammary glands to secrete milk
Anterior pituitary
- TSH
- stimulates thyroid to produce thyroxin
- ACTH
- influences the adrenal cortex
- Gonadotropic hormones
- FSH: influences follicle development
- LH: releases the egg
- Prolactin (PRL)
- stimulates milk production
- Growth Hormone
- 9 amino acids long
- secreted over a long time
- too much leads to giantism, and too little leads
to dwarfism.
Thyroid Gland
- secretes thyroxin, which regulates metabolism
- TSH, thyroxin releasing factor, effects the anterior
pituitary to produce TSH, which induces the thyroid to
produce thyroxin. This thyroxin effects target cells and
through negative feedback to the hypothalamus controls
the amount of thyroxin produced.
- Thyroxin contains iodine
- a goiter is result of lack of iodine and the result
is an enlarged thyroid gland
- an over-secretion of iodine=hyperthyroidism
- eyes get bulging quality
- nervousness
- sweating
- If not treated can cause a form of mental
retardation
Parathyroid Glands (See figure 37.12)
The interaction of PTH and calcitonin to regulate calcium levels in the blood.
Figure 37.12
- PTH
- Influences the calcium level in the blood
- If low blood calcium PTH preserves calcium
- High levels of calcium in the blood causes the
thyroid to produce calcitonin, which puts calcium
in bones and excretes it out the kidney and bladder.
Pancreas
- Makes insulin and glucagon
- Produced by islets of Langerbors, which are cells
in the pancreas/
- Insulin is a protein which takes glucose to the cells
- High blood sugar
- Pancreas secrets insulin and causes blood
glucose to be absorbed into the cells.
- Low blood sugar
- secretes glucagon and causes liver to break
down glycogen and produce glucose.
Adrenal Glands
- Have cortex (outer) and medulla (inner)
- cortex produces:
- Aldosterone: effect kidney tubules
- Cortisol: aids in adaptation to stress
- medulla produces:
- epinephrine a.k.a. adrenaline
All illistrations from Understanding Biology, 3d ed.,
by Raven & Johnson, © 1995 Times Mirror Higher Education Group, Inc.
Here is a text only version of these notes.
Here is the next set of notes.
Back to Bio 104 notes.