6.3 Nervous System Flashcards
What are the four main things that the nervous system does?
Gathers information from both inside and outside the body
Transmits information to the processing areas of the brain and spinal cord
Processes the information in the brain and spinal cord
Sends information to the muscles, glands, and organs for a response
What are the three main structures of the nervous system?
Brain
Spinal cord
Peripheral nerves
What are the two main divisions of the nervous system?
Central Nervous System (CNS) Peripheral Nervous System (PNS)
What are the components of the central nervous system?
brain + spinal cord
What are the components of the peripheral nervous system?
Contains sensory neurons, interneurons, and motor neurons.
What does the CNS do?
The CNS is the control center of the body.
The CNS interprets and responds to information from the environment and from within the body.
How many neurons does the brain have?
Contains more than 100 billion neurons.
What are the 4 different parts of the brain?
Cerebrum
Cerebellum
Brain Stem
Diencephalon (thalamus and hypothalamus)
What is the brains function in the CNS?
The brain is the body’s main processing center.
What is the cerebrum responsible for?
the capacity for learning, memory, perception, and intellectual function.
What is the left hemisphere of the brain responsible for?
Logic, language, math
What is the right hemisphere of the brain responsible for?
Creative, artistic, emotional
What are the four lobes of the cerebrum?
Frontal Temporal Parietal Occipital
What is the frontal lobe responsible for?
planning, emotional regulation, problem solving, judgement
What is the temporal lobe responsible for?
processes sensory information important for hearing, language, formation of memories
What is the parietal lobe responsible for?
integrating sensory information (EX: touch, temperature, pressure, pain)
What is the occipital lobe responsible for?
processes sensory information for vision
What does the cerebellum do?
Coordinates movement and aspects of motor learning.
Balance
Helps the body learn movements that require practice
Know where the cerebrum, cerebellum and brain stem are. Then know where the frontal lobe, parietal lobe, occipital lobe, temporal lobe, thalamus, and hypothalamus.
What does the brain stem do?
Relays information throughout the CNS and plays an important role in maintaining homeostasis
What are the 3 main parts of the brain stem?
Midbrain Pons and Medulla oblongata
What does the midbrain do?
vision, hearing, motor control
What does the Pons do?
breathing, sleep
What does the medulla oblongata?
involuntary activities (breathing, heart rate, blood pressure, body temperature)
What does the thalamus do?
Brain’s switchboard
Filters and relates information to various regions of the brain
What does the hypothalamus do and what does it regulate?
Important role in maintaining homeostasis via the regulation of
Pituitary gland and its hormones
Autonomic NS
What is autonomic NS?
Body temperature, blood pressure, heart rate, respiration, hunger, thirst, and more!
What is the spinal cord and where is it?
is a dense cable of nervous tissue that begins at the base of the brain and runs through the vertebral column. functions in involuntary movements in response to stimulus called reflex.
What are the 4 vertical columns of the spinal cord?
Cervical Nerves, Thoracic Nerves, Lumbar Nerves, Sacral nerves
Cervical nerves location and what nerve pairs?
Head to shoulder, 1-8
Thoracic nerves location and what nerve pairs?
Chest to abdomen 9-20
Lumbar nerves location and what nerve pairs?
Legs 21-25
Sacral nerves location and what nerve pairs?
Sex and bladder 26-30
What are the two principal divisions of the PNS?
Sensory and Motor
What is the sensory division?
afferent, directs sensory information to the central nervous system.
What is the motor division
efferent, Carries out responses to sensory information from the CNS to muscles or glands.
What are the two independent systems of the motor division?
Somatic, Autonomic
What is the somatic nervous system?
Controls muscles and movement; voluntary movement.
What is the autonomic nervous system?
Controls internal organs and glands.
What are the two divisions of the autonomic nervous system?
Sympathetic and Parasympathetic
What is Sympathetic ANS?
Also known as “Fight or Flight”
Commonly caused by emergencies, excitement, exercise
Increases heart rate, blood pressure, respiration, and sweating
Heightens awareness, decreases digestion
What is parasympathetic ANS?
Also known as “Rest and Digest”
Slows down responses to bring about a state of calm
Helps to maintain daily necessary body functions (EX: resting heart rate)
Decreases heart rate, blood pressure, respiration, relaxes muscles, increases digestion
What are neurons?
are nerve cells that transmit impulses (Action potentials) throughout the body.
What are the three types of neurons?
Sensory Motor Interneuron
What do sensory neurons do?
Carry impulses from sensory organs to the CNS
What do Motor neurons do?
Carry impulses from the CNS to muscles and glands
What do Interneuron neurons do?
Connect sensory and motor neurons & process impulses.
What is a reflex?
Quick/automatic response to a stimulus.
What are the 5 components of a reflex arc?
Receptor
Sensory neuron
Interneuron
Motor neuron
Effector
What is a receptor is a reflex arc?
Nerve endings that respond to changes in the internal and external environment.
What is an effector is a reflex arc?
Muscle fibers (as in the Hamstring muscle) or glands respond by contracting or secreting a product.
What are dentrites?
extend from the cell body of the neuron, are the “antennae” of the neuron.
Dendrites receive impulses from other cells.
The cell body collects impulses from dendrites, relays this information to other parts of the neuron, and maintains the general functioning of neurons.
Contains the nucleus and cytoplasm
What is an axon? What is the axon terminal?
is a long membrane-covered extension of the cytoplasm that conducts nerve impulses away from the cell body.
The end of the axon are called axon terminal.
When a neuron communicates with other cells, it does so via its axon terminal.
What is a myelin sheath
Many neurons have a layer of insulation on their axon
Presence of myelin causes nerve impulses to move faster down the axon.
What are nodes of Ranvier?
Myelin sheath is interrupted at intervals, leaving gaps
Impulses jump from one node to another
What is the speed of impulse conduction related to ?
axon diameter; large-diameter axon will conduct impulse faster than a smaller-diameter axon.
What does the nervous tissue contain?
mostly of neurons and their supporting cells.
What are nerves made of?
bundles of axons.
How do nerves appear?
fine, white threads when viewed with the unaided eye.
What is the membrane potential?
All cells have an electrical charge on the inner surface of the cell that is different from the charge of fluid outside of the cell.
The difference in electrical charge across the cell membrane is called the membrane potential, which is a result of ions going in and out of the cell.
What is resting potential?
When a neuron is not conducting a nerve impulse, the neuron is said to be at rest which is called the resting potential.
The resting potential is typically around -70 millivolts (mV).
What is a stimulus?
The neuron must be stimulated to send an impulse.
Stimulus is a change in the environment with enough strength to initiate a response.
What is action potential?
A nerve impulse is also called an action potential.
An action potential is a local reversal of polarity; from negative to positive charge.
What are the action potential steps
At resting potential, the neuron is ready to conduct an action potential.
Action potential begins when a stimulus causes a positive change in the membrane potential near the axon.
This stimulus can be due to another neuron or the environment.
Change in membrane potential causes voltage-gated sodium channels to open, allowing sodium ions to flow into the axon-> depolarization!
The opening of sodium channels cascades down the axon allowing the action potential to move down the axon toward the axon terminal.
Sodium channels close as action potential has passed.
Voltage-gated potassium channels open allowing potassium ions to flow out of the axon-> repolarization!.
Membrane potential becomes negative and resting potential is reestablished.
What is the synapse?
A small gap or space between the axon of one neuron and the dendrite of another
At synapses, neurons usually do not touch the cells they communicate with.
What is the synaptic cleft?
The tiny gap between an axon terminal and the receiving cell
What happens at the synapse?
one neuron can transfer an impulse to another neuron.
What are neurotransmitters and how are they triggered to release?
Impulses can trigger the release of chemical signal molecules called neurotransmitters into the synaptic cleft.
Neurotransmitters start an impulse the second neuron, muscle, or gland.
What are the steps to the release of neurotransmitters?
When action potential reaches an axon terminal, this causes neurotransmitter containing vesicles to fuse with the cell membrane.
Neurotransmitters (e.g. dopamine, serotonin) are released in the synaptic cleft via exocytosis.
Neurotransmitters diffuse across from the presynaptic neuron to postsynaptic neuron.
Neurotransmitters bind to receptor proteins on the postsynaptic neuron. Neurotransmitters may either excite or inhibit the activity of the cell it binds to.
What do Excitatory neurotransmitters do?
cause a new action potential.
EX: Dopamine
What do Inhibitory neurotransmitters do?
stop an action potential from occurring.
EX: Serotonin
