Unit 1 - Intro to Physiology Flashcards
The wall of the alveolus (air sac) in the lung is composed of which type of epithelium?
simple squamous epithelium
This single layer of squamous cells is ideal for the diffusion of gases in the lungs.
The proximal tubule of the nephron in the kidney is composed of which type of epithelium?
simple cuboidal epithelium
Simple cuboidal cells line the kidney tubules (nephrons) so that secretion and absorption can take place.
The epithelium of the esophagus is composed of which type of epithelial tissue?
stratified squamous epithelium
This epithelium protects underlying tissues from the wear and tear of constant swallowing in the esophagus.
Which part of the neuron (a specialized nerve cell) receives signals from other cells and is also the main metabolic region of the neuron?
soma
The soma or cell body receives inputs (signals) from other cells and sends the information to the axon. But unlike a dendrite, it is also the main metabolic and nutritional center of the cell.
Which of the three muscle cell types has multiple nuclei?
skeletal
Skeletal muscle cells are elongated and many can be quite long; therefore, they have multiple nuclei.
Which muscle cell type has visible striations but is not under voluntary control?
cardiac
Cardiac cells, like skeletal cells, have visible striations but are not under voluntary control.
What is excitable tissue?
Excitable tissue is made of cells that can alter their membrane potentials in response to a stimuli and generate action potentials. Excitable cells include neurons, muscle cells, and beta cells of the pancreas.
Which form of cell-to-cell communication uses the direct transfer of electrical and chemical signals?
Gap-junction signaling
What is the name for a competing ligand that binds to a receptor and causes the same response as the primary ligand?
agonist
Neurons that lie entirely within the CNS are called?
interneurons
Which glial cells have extensions that contact blood vessels in the brain?
astrocytes
A collection of neuronal soma in the PNS (outside the CNS) is called a _______ and within the CNS is called a _______.
ganglion (pl. ganglia); nucleus
Concentration gradients exist across the cell membrane. Specifically, there are more ________ inside and more ________ outside the cell membrane.
K+ ions; Na+ ions
The plasma membrane of a neuron is more permeable to _________.
Potassium (K+) ions
Resting membrane potential being negative (-70 mV) depends on what factors?
-the greater number of potassium leak channels
-the greater permeability of the plasma membrane to K+ ions
-the concentration gradient for Na+ ions
A neuron under the influence of a neurotransmitter that opens K+ ion
channels will ______________.
be less likely to fire an action potential
An action potential starts at the trigger zone of efferent neurons & interneurons. This is the _______ and _______.
the axon hillock; initial segment
In myelinated axons, action potential occurs at the ________ and they propagate ________.
nodes of Ranvier; rapidly
Action potential propagation in myelinated axons is known as
________.
saltatory conduction
This type of tissue provides structural support and barriers.
connective tissue
How do neurons transmit electrical impulses?
via energy stored as an electrochemical gradient
Initiating ions to enter a cell is accomplished through the binding of ____________ to __________ ___________ that open _____ ___________.
neurotransmitters; membrane receptors;
ion channels
How does the membrane potential return to the resting level?
K+ ions leave the cell (falling phase of action potential)
Why can’t an action potential be generated during the absolute refractory period?
The Na+ channel is in an inactive state
The membrane must depolarize before the Na+ channel can return to its normal resting state
