Exam 1 (Ch. 1-3) Flashcards
Neuron
Information messenger
Parts of a neuron
Dendrites, axon, and soma/cell body
Nucleus
Contains DNA and controls hereditary aspects
Mitochondrion
Powerhouse (energy) of the cell
Chromosomes
DNA molecule that contains genetic information
Ribosomes
Put proteins together
What are the two types of neurons?
Motor neuron and sensory neuron
Motor neuron
Transmits impulses from the spinal cord to skeletal and smooth muscle, and directly controls all of our muscle movements
Sensory neuron
Transmits impulses from a receptor (such as those in the eye or ear) to a more central location in the nervous system (such as the spinal cord or brain)
Dendrites
Branching fibers that receive neural signals
Can neurons have multiple dendrites?
Yes
Axon
Sends neural signals to other neurons, organs, or muscles
Do neurons have one axon or multiple?
One
Myelin sheath
Insulation that goes over axon & protects neuron signal from stopping/playing out. Without this, fine motor skills and moveability can be negatively affected.
Nodes of Ranvier
Gaps found within myelinated axons that allow the generation of a fast electrical impulse along the axon
Presynaptic terminal
Releases neurotransmitters once the neural signal comes through
Why do neurons vary in shape and size?
The shape of a neuron determines its connection with other neurons and its contribution to the nervous system. The function is closely related to the shape of a neuron.
What happens in the resting potential?
The membrane maintains an electrical gradient known as polarization. When at rest, sodium (Na) leaves the cell while potassium (K) enters. The inside of the membrane is slightly negative with respect to the outside.
What is the resting potential of a neuron?
State of the neuron prior to the sending of a nerve impulse
What happens in the action potential?
Resting potential turns into action potential when the neuron is stimulated. This is a rapid depolarization of the neuron, where it exceeds the threshold of excitation. Once this happens, the membrane (gate) of the cell opens, and sodium (Na) is let back into the cell. The inside of the membrane is now positive.
The sequence of events at the synapse
- Neuron synthesizes chemicals that serve as neurotransmitters.
- Action potentials travel down the axon.
- Released molecules diffuse across the cleft, attach to receptors, and alter the activity of the postsynaptic neuron.
- Neurotransmitter molecules separate from their receptors.
- Neurotransmitters may be taken back into the presynaptic neuron for recycling or diffuse away.
- Some postsynaptic cells may send reverse messages to slow the release of further neurotransmitters by presynaptic cells.
Function of: serotonin
Affects mood, sleep, hunger, and arousal
Problems caused by oversupply/undersupply of: serotonin
Undersupply linked to depression
Function of: dopamine
Influences movement, learning, attention, and emotion
Problems caused by oversupply/undersupply of: dopamine
Oversupply linked to schizophrenia; undersupply linked to tremors and decreased mobility in ADHD
Function of: acetylcholine (ACh)
Enables muscle action, learning, and memory
Problems caused by oversupply/undersupply of: acetylcholine
ACh-producing neurons deteriorate as Alzheimer’s disease progresses
Function of: norepinephrine
Helps control alertness and arousal
Problems caused by oversupply/undersupply of: norepinephrine
Undersupply can depress mood and caused ADHD-like attention problems
Function of: gaba
A major inhibitory neurotransmitter
Problems caused by oversupply/undersupply of: gaba
Undersupply linked to seizures, tremors, and insomnia
Function of: glutamate
A major excitatory neurotransmitter that is involved in memory
Problems caused by oversupply/undersupply of: glutamate
Oversupply can overstimulate the brain, producing migraines or seizures
Function of: endorphins
Natural painkiller
Problems caused by oversupply/undersupply of: endorphins
Undersupply can cause abnormal pain levels
Antagonist
Does opposite of neurotransmitter
Agonist
Does same function/result of neurotransmitter
Nucleus accumbens
Reward circuit & motivation; addiction is also found in this part of brain
Central nervous system
Brain and spinal cord; It takes in sensory information, process information, and send out motor signals
Peripheral nervous system
Connects the brain and spinal cord to the rest of the body
What are the two types of peripheral nervous system categories?
Somatic nervous system and autonomic nervous system
Somatic nervous system
Controls voluntary muscles and conveys sensory information to the central nervous system (ex: writing)
Autonomic nervous system
Controls the heart, intestines, and other organs
What two types of matter does the spinal cord consist of?
Gray matter and white matter
Gray matter of spinal cord
Located in the center of the spinal cord and is densely packed with cell bodies and dendrites
White matter of spinal cord
Composted mostly of myelinated axons that carries information from the gray matter to the brain or other areas of the spinal cord
Sympathetic nervous system
Network of nerves that prepares the organs for rigorous activity. Increases heart rate, blood pressure, respiration, etc. “Fight or flight” response.
Parasympathetic nervous system
Facilitates vegetative and nonemergency responses. Relaxed state/response.
Parts of the hindbrain
Medulla, pons, cerebellum
Medulla
Responsible for vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing
Cranial nerves
Allow the medulla to control sensations from the head, muscle movements in the head and many parasympathetic outputs
Pons
Arousal and attention functions. Axons from each half of the brain cross to the opposite side of the spinal cord (left hemisphere controls right side of body & vice versa)
Cerebellum
Most condensed part of the brain & is responsible for coordination, balance, and movement
Thalamus
Relays important information from the sensory organs to cerebal cortex
What is the only sense that does not cross through the thalamus?
Smell
Hypothalamus
Conveys messages to pituitary gland to alter release of hormones. Associated with behaviors such as eating, drinking, sexual behavior, and other motivated behavior.
Hippocampus
Where new memories develop
Amygdala
Emotional center
Occipital lobe
Responsible for visual output (1/4 of brain = vision)
Parietal lobe
Responsible for touch sensations
Temporal lobe
Responsible for hearing and processing spoken language
Frontal lobe
Personality channel responsible for movements and emotions
Corpus callosum
Responsible for multi-tasking; connects both hemispheres of brain
