Chapter 2: Structure and Function Flashcards
Neurons
Nerve cells, basic unit of the brain
Glial cells
Serve various functions in the nervous system, providing structural support and electrical insulation to neurons and modulating neuronal activity
Three main types of glial cells
Astrocytes, microglial cells, and oligodendrocytes
Astrocytes
Large glial cells with round or radially symmetrical forms; they surround neurons and are in close contact with the brain’s vasculature
Blood-brain barrier (BBB)
Created by astrocytes between the tissues of the central nervous system and the blood
The BBB restricts the diffusion of microscopic objects (such as most bacteria) and large hydrophilic molecules in the blood from entering the neural tissue, but it allows the diffusion of small hydrophobic molecules, such as oxygen, carbon dioxide, and hormones.
Myelin is formed by _______ in the central nervous system and _______ in the peripheral.
oligodendrocytes, Schwann cells
Microglial cells
phagocytes that devour and remove damaged cells. Unlike many cells in the central nervous system, microglial cells can proliferate even in adults (as do other glial cells)
Presynaptic
The neuron’s axon’s output synapses make connections onto other neurons or targets
Postsynaptic
Other neurons make a connection at input synapses onto their dendrites or elsewhere on the receiving neuron
Neurons communicate with other neurons and cells at specialized structures called _______.
synapses
The electrical gradient across a neuron’s membrane results from the _______.
asymmetrical distribution of ions
What makes a molecule a neurotransmitter?
It is synthesized by and localized within the presynaptic neuron, and stored in the presynaptic terminal before release.
It is released by the presynaptic neuron when action potentials depolarize the terminal (mediated primarily by Ca2+).
The postsynaptic neuron contains receptors specific for it.
When artificially applied to a postsynaptic cell, it elicits the same response that stimulating the presynaptic neuron would.
Tachykinins
(brain-gut peptides, which are peptides secreted by endocrine cells and enteric neurons in the GI tract and also neurons in the central nervous system). This group includes substance P, which affects vasoconstriction and is a spinal neurotransmitter involved in pain.
Neurohypophyseal hormones
Oxytocin and vasopressin are in this group. The former is involved in mammary functions and has been tagged the “love hormone” for its role in pair bonding and maternal behaviors; the latter is an antidiuretic hormone.
Hypothalamic releasing hormones
This group includes corticotropin-releasing hormone, involved in the stress response; somatostatin, an inhibitor of growth hormone; and gonadotropin-releasing hormone, involved with the development, growth, and functioning of the body’s reproductive processes.
Opioid peptides
This group is named for its similarity to opiate drugs, and these peptides bind to opiate receptors. It includes the endorphins and enkephalins.
Other neuropeptides
This group includes peptides that do not fit neatly into another category, such as insulins, secretins (e.g., glucagon), and gastrins.
Action potential (p. 31)
A rapid depolarization and repolarization of a small region of the membrane on the neuron’s output via its axon caused by the opening and closing of ion channels.
Amygdala (p. 50)
Collections of neurons anterior to hippocampus in the medial temporal lobe, involved in emotional processing
Association cortex (p. 61)
Part of neocortex that involves signals from different inputs (not jsut sensory or motor)
Autonomic nervous system (p. 40)
involved in controlling the involuntary action of smooth muscles, the heart, and various glands
Axon (p. 27)
The axon is a single process that extends from the cell body.
This structure represents the output side of the neuron. Electrical signals travel along the length of the axon to its end, the axon terminals, where the neuron transmits the signal to other neurons or other targets.
Axon collaterals (p. 27)
Some axons branch to form axon collaterals that can transmit signals to more than one cell.
Axon hillock (p. 32)
A part of the cell body of a neuron where the membrane potential’s are summer before being transmitted down the axon.
Basal ganglia (p. 50)
Collection of nuclei bilaterally located beneath the anterior portion of lateral ventricals
5 nuclei: caudate, putamen, globus pallidus, subthalamic nucleus, substantia nigra
action selection, action gating, reward-based learning, motor prep, timing, task switching, and more
Brainstem (p. 46)
Region of the nervous system that contains groups of motor and sensory nuclei, nuclei of widespread modulatory neurotransmitter systems, and white matter tracts of ascending sensory info and descending motor signals
Medulla, pons and cerebellum, and midbrain
Central nervous system (CNS) (p. 40)
The brain and spinal cord
Central sulcus (p. 54)
Divides frontal and parietal lobes
Cerebellum (p. 42)
“Little brain”
Coordination and movement
Cerebral cortex (p. 42)
Layered sheets of neurons over the forebrain
Commissure (p. 42)
White matter tracts that cross from left to right of CNS or vise versa
Corpus callosum is the largest
Corpus callosum (p. 42)
Fiber system composed of axons that connect the cortex of the two cerebral hemispheres
Largest white matter structure
Cytoarchitectonics (p. 54)
Brodmann used the micro anatomy of cells and their organization to subdivide the cortex into 52 regions
Can seem unsystematic and is not standardized
Dendrites (p. 26)
Dendrites are branching extensions of the neuron that receive inputs from other neurons.