Nervous System Flashcards
Parts of central nervous system
Brain and spinal cord
2 sections of nervous system
Central and Peripheral
Parts of peripheral nervous system
All nerves outside brain and spinal cord
2 different peripheral nerves
Somatic and autonomic
An example of somatic movement
Walking or jumping
Example of automatic movement
Breathing
2 different ANS systems
Sympathetic and parasympathetic
Duty of the sympathetic nervous system
Nerve cells that prepare body for stress
Duty of the parasympathetic nervous system
Restores body to resting levels and normal function after stress
3 duties of peripheral nervous system
- Works with endocrine system in adjusting body to changes in the internal and external environment
- Regulates organs of the body without conscious control
- Regulates O2 and CO2 levels
3 things the ANS can do in cases of emergency
- Divert blood flow from digestive organs to skeletal muscles
- Increase heart and breathing rates
- Increase sight by dilating pupils
What is the Vagus Nerve
Major cranial nerve apart if parasympathetic nervous system
List the sympathetic emergency response for the following organs; heart, digestive, liver, eyes, skin, bladder, and adrenal gland
Heart: increase heart rate Digestive: decrease peristalsis Liver: increase release of glucose Eyes: dilate pupils Skin: increase blood flow Bladder: relaxes sphincter Adrenal Gland: release of epinephrine
What are the 2 natural pain kills produced by the brain
Endorphins and enkephalins
What are endorphins
Group of chemicals called neuropeptides that usually have between 16-31 amino acids
What are enkephalins
Also neuropeptides but only have 5 amino acids and are made by the splitting of endorphin chains
What creates the feeling of pain
Special cells called “substantia gelatinosa” (SG) interpret pain
What are SG cells made of
They are bands of gelatinous grey matter that is in the dorsal part of the spinal cord
How do SG cells work
When SG cells are stimulated they produce a neurotransmitter that tells the injured organ it is damaged
How natural painkillers work
- Endorphins attach to SG cell receptor sites
- Prevents neurotransmitter from being produced
- Therefore less neurotransmitters which means less pain being initiated
What are Opiates
Sedative drugs like heroin, cocaine, or morphine that work in the same way as endorphins
What is GABA
GABA stands for “gamma-amino-butyric acid” which is a neurotransmitter inhibitor
What are 2 examples of a depressant drug
Valium and Librium
What happens when taking a depressant
The depressant typically increases the release of GABA
5 ways of thinking done by the left side of the brain
- Logical
- Sequential
- Rational
- Analytical
- Objective
5 ways of thinking done by the right side of the brain
- Random
- Intuitive
- Holistic
- Synthesizing
- Subjective
What is Meninges
A 3 later membrane surrounding brain and spinal cord that determines which chemicals reach the brain
The outer later of the meninges is also known as
Dura-mater
The middle later of the meninges is also known as
Arachnoid mater
The inner later of the meninges is also known as
Pia-mater
What is Cerebrospinal Fluid
Cushioning fluid that circulates between inner and middle membranes of the brain and spinal cord
What does the Cerebrospinal Fluid connect
Connects neural and endocrine system
What is the Foramen Magnum
Opening in skull that spinal cord extends through
What is process of getting information to peripheral muscles and organs
Dorsal nerve brings sensory info into spinal cord. Then ventral nerve tract sends out motor info to the muscles and organs
What are the 3 distinct regions of the brain
- Forebrain
- Midbrain
- Hindbrain
What are Olfactory Lobes
Pair of lobes in forebrain that receives info about smell
What is the Cerebrum
2 huge hemispheres in forebrain that stores sensory info and initiates voluntary motor actions
What is the Cerebral Cortex
Outer lining of the Cerebral Hemispheres
What side of the brain is associated with visual patterns
Right side
What side of the brain is associated with verbal skills
Left side
What is the Corpus Callosum
A bundle of nerves that allows communication between the 2 hemispheres
Each hemisphere can be sub-divided into what 4 lobes
- Frontal
- Temporal
- Occipital
- Parietal
What is the Thalmus
Part of brain that interprets sensory info and directs it to the cerebrum
What is the Hypothalmus
Located below Thalmus and creates a direct connection between the nervous and endocrine system through the Pituitary Gland
The Midbrain acts as what
A relay centre for some eye and ear reflexes
The hindbrain joins with what
The spinal cord
What are the 3 major hindbrain sections
- Cerebellum
- Pons
- Medulla Oblongata
What are 2 features of the Cerebellum
- Largest section
2. Controls limb movements, balance, and muscle tone
What are 2 features of the Pons
- Means “bridge”
2. Passed info between regions of the cerebellum and between cerebellum and the medulla
What are 4 features of the Medulla Oblongata
- Nerve tracts from spinal cord and higher brain centres run through the medulla
- Acts as a connection between the PNS and CNS
- Controls involuntary muscle action such as breathing
- Acts as coordination centre for Autonomic Nervous System
4 things about a PET Scan
- ‘Positron-emission tomography’
- Can reveal physiological and biochemical process in the body
- A molecule tagged with radioactive isotope is injected in body and flows to most active area of the brain
- The positrons react with opposing charged electrons from body atoms which creates a image
What is a PET Scan used to spot
Brain disorders, heart problems, and certain types of cancer
7 things about a MRI Scan
- ‘Magnetic resonance imaging’
- fMRI = functional MRI
- Computer imaging technique that can make 2D and 3D images of the brain
- fMRI measures function > structure
- MRI uses powerful magnets to align nuclei in the brain then knock them out of alignment with a quick pulse of radio waves
- While still under magnet, when hydrogen nuclei snap back into alignment, faint radio waves are emitted
- MRI detects these waves and transmits it all into a computer image
What is a MRI Scan used to detect
Problems in the brain and spinal cord which are surrounded by bone
3 things about a CT Scan
- ‘Computerized tomography’
- Machine circles patient while taking various x-rays of structures inside the body
- The various thin x-rays are sent to a computer where they can be analyzed in sections or be put together to create a 3D image
What is a CT Scan used to detect
Useful for spotting ruptured blood vessels in the brain
What are Baroreceptors
Pressure receptors in the skin
What are the 2 cells in the Nervous System
- Glial Cell
2. Neurons
What are the 3 groups of Neurons
- Sensory neurons
- Interneurons
- Motor neurons
2 things about Sensory Neurons
- Also known as “afferent” neurons
2. Carries impulses from sensory receptors to the CNS
4 things about Interneurons
- Also known as “association” neurons
- The link within neurons and the body
- Mostly found throughout brain and spinal cord
- Interprets sensory info and connects neurons to outgoing motor neurons
3 things about Motor Neurons
- Also known as “efferent” neurons
- Relays info to the effectors
- Muscles, organs, and glands are effectors as they produce the response
What are Dendrites
Projections of cytoplasm that carries nerve impulses away from cell body
What is an Axon
Extension of cytoplasm that carries nerve impulses away from cell body
What is Myelin Sheath
Fatty protein that acts as an insulator for the neurons
What are Schwann Cells
Glial cell that produces the myelin sheath
What are Nodes of Ranvier
Gaps between the multiple sections of myelin sheath
What is Neurilemma
Delicate membrane beneath the myelin sheath that covers to axon of some nerve cells
If you put your hand on something hot then your body instinctively removes your hand from the hot surface… What is this a result of
Reflex Arc
3 things about the Reflex Arc
- Simplest nerve pathway
- At the end of the sensory neuron, the Interneuron splits on a path to the brain as well as a path back to the effector
- By cutting out the process of going to the brain, it saves plenty of time and saves the body from serious damage
What are the 5 components of the Reflex Arc
- The receptor
- Sensory neurons
- Interneurons
- Motor neurons
- The effector
What is an EEG
It is an Electroencephalogram which is used to measure brain-wave activity
Nerves use what to generate current
They use cellular energy
What is Action Potential
Voltage difference across nerve cell membrane when nerve is stimulated
What is Resting Potential
Voltage difference during resting stage (usually negative)
The resting membrane is what
Resting membrane is 50x more permeable to potassium than it is to sodium
What are Ion Gates
Protein channels that control movement of ions across cell membrane
What is Polarized Membrane
Membrane charged by unequal positive charged ions inside and outside of nerve cell
What happens to the membrane during stimulation
The membrane becomes more permeable to sodium rather than potassium
What is Depolarization
After sodium ions rush in, the charge of membrane is reversed
What is a Sodium-Potassium Pump
Mechanism that moves Na ions out of and K ions into a cell against their concentration gradient
What fuels the Sodium-Potassium Pump
ATP fuels the pump
What is the ratio the Sodium-Potassium Pump works at
3 Na ions out : 1 K ion in
What is Repolarization
Process of restoring original polarity of nerve membrane
What is the Refractory Period
Recovery time required for a neuron to produce another Action Potential (usually 1-10ms)
What is the Threshold Level
The lowest level of stimulus required to produce a response
What is the “All-or-None” response mean
This means a nerve or muscle fibre will either respond completely or not at all
With greater impulses reaching the brain, this causes what
It will cause greater intensity of a response
What is Synapses
Regions between neurons or between neurons and effectors
What are Neurotransmitters
Chemicals located in the end plates of axons and are released from vesicles into synapses
What is a Presynaptic Neuron
Neuron that carries impulses to the synapse
What is the space between neurons
20um
What is a Postsynaptic Neuron
Neuron that carries impulses away from synapse
What is Acetylchloine
Neurotransmitter that makes Postsynaptic membrane no longer permeable to Na ions
What is Cholinesterase
An enzyme that breaks down acetylcholine as it is released from Postsynaptic membrane shortly after acetylcholine is released
What does it mean when something is Hyperpolarized
This is when the inside of a nerve cells membrane becomes more negative than the resting potential
What is Summation
An effect produced by the accumulation of neurotransmitters from 2 or more neurons
