Nervous System & Hormones Flashcards
Highly specialized cells responsible for the conduction of impulses.
Neurons
This communication occurs via ion exchange and the generation of membrane potentials down the length of the axon.
Electrical Communication
This communication occurs via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell.
Chemical Communication
Appendages that recieve signals from other cells.
Dendrites
The location of the nucleus as well as organelles such as the endoplasmic recticulum and ribosomes.
Soma
Where the cell body transitions to the axon, and where action potentials are initiated.
Axon Hillock
A long appendage down which an action potential travels.
Axon
The end of the axon from the neurotransmitters released.
Nerve Terminal (Synaptic Bouton)
Exposed areas of myelinated axons that permit saltatory conduction.
Nodes of Ranvier
An insulating substance that prevents signal loss. Prevents dissipation of the neural impulse and crossing of neural impulses from adjacent neurons.
Myelin
A cluster of cell bodies of neurons of the same type within a nerve, in the PNS.
Ganglia
A cluster of cell bodies of the individual neurons within a tract, in the CNS.
Nuceli
How is myelin made (CNS vs. PNS)?
- CNS: created by oligodendrocytes
- PNS: created by Schwann Cells
These cells nourish neurons and form the blood-brain barrier; which controls the transmission of solutes from the bloodstream into the nervous tissue.
Astrocytes
Cells that line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber.
Ependymal Cells
Cells that are phagocytic and ingest/break down waste products and pathogens in the central nervous system.
Microglia
This pump is used to maintain resting membrane potential. It pumps 3 sodiums out of the cell for every two potassium ions pumped in.
Na+/K+ Pump
Refers to the addition of multiple signals near each other in time.
Temporal Summation
Refers to the addition of multiple signals near each other in space.
Spatial Summation
In this reflex, the sensory neurons (presynaptic) neuron fire directly onto the motor (postsynaptic) neuron.
Monosynaptic Reflex Arc
In this reflex, the sensory neuron may fire onto a motor neuron, as well as interneurons that fire onto other motor neurons.
Polysynaptic Reflex Arc
Hormones composed of amino acids and are derived from larger precursor proteins that are cleaved during posttranslational modification. Also, these hormones are polar and cannot pass through the plasma membrane.
Peptide Hormones
Hormones derived from cholesterol that are minimally polar and can pass through the plasma membrane.
Steroid Hormones
Hormones that are modified amino acids. Their chemistry share some features with peptide and steroid hormones. These share different features than other hormone classses (ex. epinephrine, triiodothyronine, and thyroxine).
Amino Acid-Derivative Hormones
Hormones that have major effects in non-endocrine tissues.
Direct Hormones
Hormones that have major effects in other endocrine tissues.
Tropic Hormones
Stimulates follice maturation; spermatogenesis.
Follicle-Stimulating (FSH)
Stimulates ovulation; testosterone synthesis.
Lutenizing (LH)
Stimulates the thyroid to produce thyroid hormones.
Thyroid-Stimulating (TSH)
Stimulates adrenal cortex to make and secrete glucocorticoids.
Adrenocorticotropic (ACTH)
Stimulates milk production and secretion.
Prolactin
Inhibits perception of pain in the brain.
Endorphins
Stimulates bone and muscle growth/lipolysis.
Growth Hormone (GH)
Stimulates uterine contractions during labor, milk secretion during lactation.
Oxytocin
Stimulates water reabsorption in kidneys via low volume AND high blood osmolarity.
Antidiuretic Hormone (ADH, Vasopressin)
Stimulates metabolic activity.
Thyroid Hormones (T3 and T4)
Decreases (tones down) blood calcium levels.
Calcitonin
Increases blood calcium levels.
Parathyroid Hormone (PTH)
Increases blood glucose level and decreases protein synthesis; anti-inflammatory.
Glucocorticoids
Increases sodium and water reabsorption in kidneys.
Mineralocorticoids
Increases blood glucose level and heart rate.
Epinephrine and Norepinephrine
Stimulates conversion of glycogen to glucose in the liver; increases blood glucose.
Glucagon
Lowers blood glucose; increases glycogen stores.
Insulin
An inhibitor of both insulin and glucagon secretion. High blood glucose and amino acid concentrations stimulate it’s secretion.
Somatostatin
Promotes growth/maintenence of endometrium.
Progesterone
Helps regulate salt and water balance via atria heart cells. When cells in the atria are stretched from excess blood volume, they release this hormone, which promotes excretion of sodium and therefore increases urine volume (antagonistic to aldosterone because it lowers volume, NOT osmolarity).
Atrial Natriuretic Peptide (ANP)
Stimulates T-cell development.
Thymosin
What are the three distinct types of cells throughout the pancreas (Islets of Langerhans)?
- Alpha - Secrete Glucagon
- Beta - Secrete Insulin
- Delta - Secrete Somatostatin
