The Brain and Nervous System Flashcards
What is the human nervous system and what are its two functions?
It is the network of nerve cells and fibers which transmits nerve impulses (messages) between parts of the body. It receives and processes sensory info from the environment and it transmits motor info around the body.
Describe motor and sensory info
sensory; information about the external environment carried from sensory organs
motor; information about how to respond to external environment carried from brain to internal organs (e.g muscles)
What are the two major divisions of the Nervous system and what do they consist of?
Central Nervous System (Brain & Spinal Cord)
Peripheral Nervous System (all other nerves)
Draw the human nervous system
Nervous system > central and peripheral nervous system > brain/spinal cord and automatic/somatic nervous system > sympathetic/parasympathetic and sensory info/voluntary skeletal muscles
What does the spinal cord do and what are its functions?
It connects the brain to the rest of the body. Functions = 1) Send info from sensory neurons in various parts of the body to the brain & 2) Relay motor commands back to muscles and organs via motor neurons
What is the function of the Brain?
The Brain receives and processes information and coordinates a response.
What is the Peripheral nervous system and what does it do?
The Peripheral nervous system is connected to the spinal cord and consists of all nerves outside the CNS. It carries sensory info from body to CNS and motor info from CNS to body. It consists of the Somatic (voluntary) and Autonomic (involuntary) NS.
Compare the roles of the CNS and the PNS?
CNS; receive and process info and coordinate response
PNS; take sensory info to CNS and motor info from CNS to body.
Explain the role of the somatic nervous system?
Somatic nervous system transmits sensory info to CNS and carries out its motor commands. It is involves in voluntary skeletal movements.
Explain the role of the autonomic nervous system?
Autonomic nervous system is responsible for autonomic responses. It carries info between CNS and internal bodily structures (e.g heart) It is divided into two main systems; Sympathetic and Parasympathetic.
Describe the sympathetic nervous system and examples
Sympathetic nervous system = readies the body for fight or flight response when its exposed to threats (stressors)
Examples = dilates pupils, increases heart rate, slows down digestion
Describe the parasympathetic nervous system and examples
Parasympathetic nervous system = slows things down and calms body down after a stress response and maintains homeostasis.
Examples = pupils constrict, heart rate lowers, digestion increases
What are the types of neurons, where are they located and what are their roles?
Sensory (PNS)(Afferent) = transmit info from sensory organs to brain
Motor (PNS)(Efferent) = transmit commands from interneurons to the glands, organs and muscles of the body
Interneurons (CNS) = organize and integrate sensory info in the brain and initiate and coordinate motor responses.
Function of dendrites?
Receives input from other neurons
Function of cell body/soma?
Contains the nucleus which controls the neuron
Function of axon?
Transmits information to other neurons
Function of myelin sheath?
Protects and insulates axon and speeds up speed of neural transmission
Function of axon terminal?
Allows for the branching out of the axon contains synaptic knob at end of terminal
Function of synaptic knob?
Contains vesicles which release neurotransmitters when moving signals to adjacent cells
Function of synapse?
The space between neurons where transmission occurs
How do neurons communicate?
Electrochemical energy
Explain the two types of communication for neurons
Electrical - within the neuron > electrical impulse is transmitted along the axon
Chemical - between neurons > takes place in synapse when neurotransmitters are send from axon terminals of the pre-synaptic neuron to the dendrites of the post-synaptic neuron
What do Glial cells do and what are some of their functions?
Glial cells provide the structural framework that enable a network of neurons to remain connected. Functions = supply oxygen and nutrients to neurons so they can function, destroy and remove dead neurons, soak up excess neurotransmitters at the synapse that can clog communication between neurons
What is the synapse?
The area where neurons meet (but can never physically touch)
Describe the process of chemical communication
- Vesicles store neurotransmitters within the nerve cell
- When an action potential reaches the axon terminals, the synaptic vesicles release neurotransmitters into the synapse
- These neurotransmitters attach to the receptor sites of the post synaptic neuron and alter its action.
Describe the lock and key process
Lock = receptor site
Key = neurotransmitter
The neurotransmitter will bind with the receptor site if there is a complementary molecular structure.
Describe what happens after the neurotransmitter binds to the receptor site
-Inhibitory response; they inhibit the post synaptic neuron and make it less likely to fire an action potential
-Excitatory response; the excite the post synaptic neuron and make it more likely to fire an action potential.
Provide an example of an excitatory neurotransmitter (and what happens with too much of it)
Glutamate = more likely to fire an action potential when binded with a receptor site. Associated with cognition, memory, learning, behaviour etc
Too much glutamate > abnormal neural development, neurodegenerative diseases
Provide an example of an inhibitory neurotransmitter (and what happens with low levels)
GABA = less likely to fire action potential, slows down neural transmission and reverses effect of excitatory neurotransmitters.
Low levels = high levels of anxiety
What is the cerebral cortex?
It is the outer layer of the cerebrum, divided into two halves called hemispheres and plays a key role in memory, cognition, thought etc
Function and structure of cerebral cortex
Function; Receive and process sensory info & initiate motor response
Structure; Two hemispheres (left and right) and four lobes in each hemisphere
What does contralateral organization mean?
It means opposite sides. The right hemisphere receives sensory info from the LHS of the body and controls movements on the LHS of body. The opposite is true of the left hemisphere.
What does hemispheric specialisation mean?
The brain functions as a whole but the right and left hemispheres do seem to have specialized roles.
Functions of left hemisphere?
Speaking, logical reasoning, writing, sensory and motor functions from the RHS of the body