Hormones - ANSWER-chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ, often a considerable distance away
What are the four principal mechanisms of communication between cells? - ANSWER--Gap junctions
-Neurotransm...
BIO 202 Exam 1 Questions & Answers 100% Accurate
Endocrine system - ANSWER-glands, tissues, and cells that secrete hormones
Endocrinology - ANSWER-the study of this system and the diagnosis and treatment of its disorders
Endocrine glands - ANSWER-organs that are traditional sources of hormones
Hormones - ANSWER-chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ, often a considerable distance away
What are the four principal mechanisms of communication between cells? - ANSWER--
Gap junctions
-Neurotransmitters
-Paracrines
-Hormones
Gap junctions - ANSWER-Pores in cell membrane allow signaling molecules, nutrients, and electrolytes to move from cell to cell
Neurotransmitters - ANSWER-Released from neurons to travel across synaptic cleft to second cell
Paracrines - ANSWER-Secreted into tissue fluids to affect nearby cells
Secretion of hormones can be triggered by - ANSWER--Blood chemistry (Ca++ levels and PTH), -Other glands (Pituitary) and hormones (calcitriol)
-Nervous system Sympathetic input (Epinephrine from the adrenal gland in response to Fight or Flight)
Effects include the following changes in the metabolism of the target cells - ANSWER--
changes in membrane permeability (gates) -changes in protein synthesis (DNA) -changes in cell mitosis (growth) -changes in protein activation (enzymes)
Classes of Hormones - ANSWER--Amines Derived from single amino acids (Norepinephrine) -Peptides 3 or more Amino acids (most hormones) -Steroids Derived from Cholesterol (these are lipid soluble)
Mechanisms of action in most cases - ANSWER-Regulated by negative feedback i.e. if hormone levels rise too high...... hormone will act to inhibit the trigger
Endocrine system diagram - ANSWER-
Peptide hormones - ANSWER--Cannot penetrate target cell
-Bind to surface receptors and activate intracellular processes through second messengers
Steroid hormones - ANSWER--Penetrate plasma membrane and bind to internal receptors (usually in nucleus)
-Influence expression of genes of target cell
-Take several hours to days to show effect due to lag for protein synthesis
Pineal gland Location - ANSWER-Attached to roof of third ventricle beneath the posterior end of corpus callosum
Pineal gland Function and hormone - ANSWER--May synchronize physiological function with 24-hour circadian rhythms of daylight and darkness
-Synthesizes melatonin from serotonin during the night
-Fluctuates seasonally with changes in day length
How is the Pineal gland stimulated or regulated in humans and how is it regulated in reptiles? - ANSWER--Humans:visual system or eyes -Reptiles "skylight"
How many hormones are produced in the hypothalamus? - ANSWER-8
How many hormones in the hypothalamus regulate the anterior pituitary and what are they? - ANSWER--6
-TRH, CRH, GnRH, and GHRH (stimulating hormones)
-PIH and somatostatin (inhibitory)
How many hormones in the hypothalamus are released into capillaries in the posterior pituitary and what are they? - ANSWER--2
-ADH (antidiuretic hormone) and Oxytocin (OT)
The Hypothalamus exerts homeostatic control of the following functions - ANSWER-
Hunger, Thirst, Temperature, Blood pressure, Heart Rate, Electrolyte balance, Sleep and body rhythms
Hypothalamo-Pituitary-Target Organ Relationships - ANSWER-
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