Chapter 1 - The Nervous System Flashcards
K+/Na+: which cation has a high concentration outside a neuron?
Na+
What is the purpose of a neuron’s ATPase pump?
It generates the asymmetrical concentration gradient of Na+ and K+ across the cell membrane. It pumps Na+ out and K+ in.
What cation movement generates an action potential?
a rush of Na+ ions entering the cell once a threshold potential has been reached
What are the ion channels in an axon called?
ionophores
What is hyperpolarization?
As K+ rushes out of the neuron during repolarization, the membrane potential passes its original resting state.
What is saltatory conduction?
An action potential on myelinated nerves seems to jump from node to node.
How does ATP affect the binding of actin and myosin?
It reduce’s myosin head affinity for actin.
What role does the pituitary gland play?
It is the master endocrine gland, receiving information from the hypothalamus.
Where do sympathetic nerves originate?
from the thoracic and lumbar portions of the spinal cord
Where do somatic nerves synapse?
directly on skeletal muscle
What are first-order sensory neurons?
They carry information from the receptive field to the spinal cord.
What is troponin?
a multi-subunit binding protein that interacts with actin, tropomyosin, and Ca2+
Which cerebral lobe is associated with touch and stretch sensation?
parietal
What hormones does the adrenal medulla release?
epinephrine and norepinephrine
Where and how do exocrine glands secrete substances?
into the lumen by way of a duct
Under aerobic conditions when glucose is oxidized to CO2 and H2O, how much ATP is formed?
36 molecules ATP
As a receptor potential increases above a threshold, what happens to the action potential of the neuron?
It will increase in frequency, not in amplitude.
An active neuron has greater permeability to Na+ or K+?
Na+
What is the purpose of histamines?
They cause an increase in blood flow to regions that have been affected by allergy, infection, or injury.
What is the purpose of erector muscles?
They straighten the hair shaft.
What is the protein that coils around actin?
tropomyosin
What do mast cells secrete?
histamines
Where is acetylcholine synthesized?
in the cytosol of a neuron
When muscle is in a relaxed state, what is bound to the myosin heads?
ATP
