Exam 1 Flashcards
What is the action potential?
The action potential is the electric signal that propogates down the axon and triggers communication across a synapse
Where does the Action Potential start?
The action potential starts at the axon hillock when it is depolarized to threshold
Is depolarization the increase or the decrease of positive charge?
Increase of positive charge
What is hyperpolarization?
The increase of negative charge
Are there more or less K+ ions outside the cell?
Less
Are there more or less Cl- ions outside the cell?
More
Are there more or less Na+ ions outside the cell?
More
Are there more or less Ca2+ ions outside the cell?
More
Fill in the blank; the farther the receding electrode, the ____ the action potential reaches the electrode
later
Is the AP an all or one phenomenon?
yes
How are action potentials spread?
They are regenerated across the axon
Explain what a graded potential is
Small changes in the membrane potential of a neuron due to depolarization or hyperpolarization
What is the threshold to initiate an action potential?
-60 mv
Draw an action potential
curve with flat line at -65 mv
T or F: either the action potential happens, or it doesn’t
T
How does magnitude and direction vary with action potentials?
It doesn’t
Summarize the action potential
the cell/axon hillock is depolarized to threshold, activating vg na+ channels that further depolarize the neuron. Then, the vg na+ channels inactivate and k+ channels open, letting the potassium go out and allowing hyperpolarization to occur. VERIFY
When do voltage gated potassium channels close
at the end when membrane potential is at rest again
Why does the action potential only travel in one direction?
Voltage gated sodium channels deactivate, meaning they can no longer depolarize until they reset back to close; they cannot pass a current.
What are the two nervous systems under the pns?
Somatic and autonomic
What does the somatic nervous system do?
Innervates muscles and control conscious body movements. Sensory nerves relate info from the body to the brain and motor nerves can carry commands to create muscle movement. Also includes cranial and spinal nerves
Autonomic nervous system description
Involuntary aspects of body, such as pupil dilation and blood vessel constriction. Further divided into sympathetic and parasympathetic nervous systems
Hypothalamus
Hormone regulator, emotion, and motivations
Corpus callusom
Connects two hemispheres of brain
Thalamus
Sensory processing, arousal
Cerebellum
Motor control
Medulla and pons
Live saving actions like breathing and swallowing, pons origin for many cranial nerves
Broca’s area
Speech production
Precentral gyrus
Important for motor control, located in frontal lobe
Postcentral gyrus
A strip of cortex behind central sulcus, responsible for touch
Sylvian fissure (aka lateral sulcus
Boundary of temporal lobe- separates lobe from other regions
Central sulcus
Boundary of frontal and parietal lobe
Prefrontal cortex
Planning, impulse control, decision making
Parietal Lobe
Located in center, responsible for planning/impulse control but also sensory info
Parietal association areas _______
integrate information from different sensory modalities
Temporal lobe
auditory cortex, language, auditory, and visual areas.
Wernicke’s area
Language production and comprehension
Inferior temporal cortex
Visual identification
Occipital lobe
Primary visual cortex contains a map of visual space
Secondary visual areas that process individual components of a scene
List the important gyri and sulci
Sylvian fissure- boundary of temporal lobe
Central sulcus- boundary of frontal and parietal lobe
Precentral gyrus- in frontal lobe, important for motor control
Postcentral- A strip of cortex behind central sulcus, important for touch
What is a gyri and what is a sulci?
Gyri- raised folds on cerebral cortex, sulci are depressions
Cerebral cortex
Outer wrinkly layer of brain, the result of folding of tissue, mostly dendrites, cell bodies, and axonal projections of neurons
Basal ganglia
Group of subcortical nuclei mainly responsible for movement
Motor coordination+control
The “basal ganglia” refers to a group of subcortical nuclei responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions.
Limbic system
emotional system of the brain, with hippocampus, hypothalamus, thalamus, frontal lobe, olfactory bulb, and amygdala
Midbrain
roles in vision, audition, movement
White vs gray matter
Gray matter- cell bodies and dendrites
White matter- myelinated axons
Saggital plane
Left and right
Coronal plane
Anterior and posterior
Horizontal plane
upper and lower
Meninges
Dura (tough outside)
Arachnoid (middle, connects dura and pia, web like appearance, keeps the brain in place
Pia (soft, innermost layer, on brain surface)
True or false: the nerves that make up the somatic nervous system are the cranial and the spinal nerves
True
How many pairs of cranial nerves are there?
12- olfactory, optic, vestibulocochlear (balance), spinal accessory (control neck muscles)
Name the spinal sections from top to bottom
Cervical, thoracic, lumbar, sacral
How many pairs of spinal nerves are there?
31, one member of each pair serves a side of the body
What is each spinal nerve composed of?
A group of motor fibers, projecting from the ventral (front) part of the spinal cord to the organs and muscles, and a group of sensory fibers that enter the dorsal part of the spinal cord (remember that this is all within the somatic nervous system still)
Why is it called the autonomic nervous system?
Stems from the idea of being “autonomous”- we have little conscious, voluntary action over things such as digestion or blood vessel constriction
What are the two major divisions of the autonomic nervous system?
Sympathetic and parasympathetic- act more or less in opposition with one another
Describe characteristics of the sympathetic nervous system
Axons of the sympathetic nervous system exit from middle parts of the spinal cord, travel a short distance, then innervate the sympathetic ganglia which run in two chains along the spinal column. Axons from the sympathetic ganglia then course throughout the body, innervating major organ systems. Axons from the sympathetic ganglia mainly prepare the body for immediate action- increased blood pressure, dilated pupils, rapid heatbeat, etc
Describe the parasympathetic nervous system
Helps the body to relax, recuperate (rest and digest). These nerves originate from brainstem abd in the sacral spinal cord (which makes sense because para means around- around the sympathetic nervous system). These nerves travel a longer distance before terminating in parasympathetic ganglia, usually located close to the organs they serve.
True or false: organs receive different neurotransmitters from the sympathetic and parasympathetic nervous systems
True- norepinephrine from sympathetic nerves and acetylcholine from parasympathetic nerves
What does the spinal cord do?
Funnels sensory info from the body to the brain and also conveys commands out to the body
Why is the cortex folded up?
Increases surface area and amount of cortex that can be crammed into the skull
T or F: folding of cortex is random and individual to each person
F
Medial
towards middle
Lateral
towards the side
Ipsilateral
same side
Contralateral
opposite sides
Superior
Above
Inferior
Below
basal
towards base or bottom
anterior/rostral
front
posterior/caudal
back
proximal
near center
Distal
towards periphery
dorsal
back
ventral
tummy
affervent vs effervent
A- carries info into area of interest, effervent- carries info away
What are the four lobes and where are they located
Frontal lobe- very front, parietal lobe- middle, occipital lobe- back, temporal lobe, bottom
What symptoms would someone with cortical damage exhibit
depends on region– personality changes, visual impairments, speech errors, changes in sensation, etc
describe the difference between grey and white matter
interior is white matter (transmits), w/myelin, exterior grey matter is the cell bodies that form the outer layers of the cortex (receives/processes) and nuclei within the brain
Basal ganglia
consists of caudate nucleus, putamen, and globus pallidus
limbic system
curled around basal ganglia, , widespread network of struvtures involved in emotion and learning
amygdala
emotion, odor perception
hippocampus and fornix
learning and memory
cingulate gyrus
direction of attention
Astrocytes
most numerous cell type within the central nervous system (CNS) and perform a variety of tasks, from axon guidance and synaptic support, to the control of the blood brain barrier and blood flow. NT cleanup/reuptake
Oligodendrocyte
produce the myelin sheath insulating neuronal axons (analogous to Schwann cells in the peripheral nervous system), although some oligodendrocytes (called satellite oligodendrocytes) are not involved in myelination.
Microglia
Microglial cells are a specialised population of macrophages that are found in the central nervous system (CNS). They remove damaged neurons and infections and are important for maintaining the health of the CNS. Engulf+destroy
