What Are the functions of the Nervous System?
- 1. Reception- recieve stimuli/ sense a change
- 2. Conduction- info is carried as impulses to and from the brain and spinal cord
- 3. Response- Reaction to the stimulus/stimuli
What are Receptors?
nerve cells that enabel humans to be aware of their environment (eyes, nose, skin, etc)
What are the divisions of the Nervous System?
- CNS (Central Nervous System)- control center in the middle of your body (brain and spinal cord)
- PNS (Peripheral Nervous System)- outside the brain and spinal cord (sensory nerves and motor nerves)
What are Sensory Nerves?
- Afferent Fibers
- carry impulses to the CNS
What are Motar Nerves?
- Efferent Fibers
- Carry out of the CNS (movement and action)
What is a Neuron?
- a nerve cell
- highly modified
What are the 3 major parts of a neuron?
- 1. Cell Body- controls impulses; nucleus and mitochondria; main portion of the cell
- 2. Dendrites- also called afferent process. one or more branches that carry the impulse into the cell body.
- 3. Axon- also called the efferent process. one extra long branch that carries the impulse away from the cell body
What are ganglia?
cell bodies outside the CNS
What is the afferent process?
the message comming into a cell body
What is the efferent proccess?
the message leaving the cell bodyp
What is the myelin sheath?
- increses the speed of an impulse
- only in some neurons
What makes up the Myelin Sheath?
Schwan cells that wrab around the axon
What are the Nodes of Ranvier?
- located between the myelin sheath
- help in speeding up reactions
- in a myelinated cell the Na+ come in at the nodes of ranvier
What is an electrochemical signal?
- also called Impulse
- deals with electricity and chemicals
What is the resting state? (picture too)
- K+ and mostly negative ions inside axon, positive Na+ on the outside
- fewer positive ions sitting on the inner face of the neurons plasma membrane than
- there are on its outer face in the tissue fluid that surrounds it
- the stimulus is inactive
What is Depolarization? (pictrure too)
- Resting potential decreased and after sodium gates open, Na+ ions diffuse into the axon, making the inside more positive and the outside more negative
What happens after depolarization?
the axon teminals open and neurotransmitters travel through the synapse and deliver the impulse to the dendtrites of the next neuron
What is the synapse?
The space between the axon terminals and the dendrites of the next neuron.
What does a depolarized neuron look like?
What is Repolarizaton? (picture too)
- The membrane of the axon becomes impermeable to sodium and K+ ions exit the axon making the inside negative again and the outside positive.
What is the difference between a myelinated cell and an unmyelinated cell? (picture too)
- In a myelinated cell the Na+ can come in at each node of ranvier rather than come in at every opening, which is what it does in an unmeylinated cell. Myelinated cells complete the same task faster and are usually used for vital functions such as heartbeat.
What is the Reflex arc?
the coordinated transmission of an impulse over sensory, inter and motor neurons involved in reflexes
What are the four parts of the reflex arc?
- 1. Receptor must be stimulated (sensory receptor)
- 2. Impulse travels over a sensory neuron to the CNS
- 3. Inter neurons in the CNS transfer imoulses to the motor neurons
- 4. Impulses tracel through the motor neurons to the muscles/glands for a reaction
What is the synapse?
The space between the ason terminals of once neuron and the dendrites of the next neuron
What is a reflex?
- the response to an impulse over a reflex arc.
- ex: blinking, sneezing, coughing
What is the Reaction Time?
- the time it takes for an impulse to travel over a reflex arc.
- can be faster or slower depending on the person
What is the Threshold?
- the minimum level required to generate an impulse
- Where the axon fires
What is the sub threshold?
- not enough stimuli to create an impulse
- below the threshold
What is the All or None Law?
- also called nerve impulse or action potential
- says that if the threshold is met, it will generate an impulse all the way through even if the pressure, smell, etc stops.
- If the threshold is not hit, no impulse will be generated.
How much does the human brain weigh?
What protects the brain?
- the skull
- 3 membrane layers
What are the 3 membranes protecting the brain?
- 1. Dura Mater- outermost membrane protecting the brain
- 2. Arachnoid- middle membrane, looks like a spiderweb
- 3. Pia Mater- innermost membrane
What do the 3 membranes also protect in the same order?
What is the brainstem?
- looks like a mushroom
- connects brain to spinal cord
What are the 3 parts of the brainstem
- 1. Medulla Oblongata- lowest part of the brain stem; attaches to the spinal cord; has reflex centers for heart & lungs
- 2. Pons- above the medulla oblongata. controls breathing; has many tracks/axons running through it.
- 3. Midbrain- tracks for hearing and vision; cirucular part inside of actual brain
What do all 3 parts of the brainstem contain?
sensory nerves that conduct impulses to higher parts of the brain and motor nerves that conduct impulses from higher parts of the brain to the spinal cord
What is White Matter?
What is Grey matter?
What is the order of white and grey matter covering the brain?
- Grey Matter: Outside
- White Matter: Inside
What is the order of white and grey matter covering the spinal cord?
- Grey Matter: Inside
- White Matter: Oustide
What is the relative refractory period?
right after the period of repolarization
What is the absolute refractory period?
period when a neuron can't be restimulated because its sodium gates are open
Picture of brain w/ matter
What is the Frequency of impulses?
Codes for intensity of the stimulus
What is the cerebrum?
largest, uppermost and outermost part of the brain
What is the function of the cerebrum?
more complex sensory and motor functions
What is he Cerebral Cortex?
- the outermost layer of the cerebrum
- functions: ability to reason, memory, judgement, will power, ability to perservere, voluntary muscle contraction, vision, hearing, speech
What are the 4 parts of the cerebral cortex?
- 1. Frontal: located under frontal bone in front
- 2. Parietal: top back under parietal bone
- 3. Temporal: sides
- 4. Occipital: lower back
What is the corpus collosum?
joins the left and right sides of the brain together
What are Gyrus's
hills (bumps that stick up in the brain)
What are Sulcus's?
valleys (deep lines in the brain)
What is the deepest sulcus?
What is the Interbrain?
- also called diencephalon
- located above the midbrain andbelow the cerebrum
- inside the brain, not visible from the outside
- has 2 major structures
What are the major structures of the interbrain? Explain.
- Hypothalmus: lower part deals with alimentary canal (digestive system) controls teperature, sleep, water balance, matabolism, and emotional responses
- Hypothalmus functions through the Pituitary gland:deals w/ hormones
- Thalmus:upper part of the interbrain, deals with emotions of pleasentness unpleasentness in regards to sensation
What is the Cerebellum?
- underneath occiputal lobe
- below cerebrum
- behind brainstem
- looks like a shell
What are the functions of the cerebellum?
- balance and percise movements (hand eye coordination)
- affected easily by alcohal
What are Cranial Nerves?
- nerves that come directly off of the brain
- still part of the PNS
Name the Cranial Nerves in order (no types of nerve or function)
- 1. Olfactory
- 2. Optic
- 3. Oculomotor
- 4. Trochlear
- 5. Trigeminal
- 6. Abducens
- 7. Facial
- 8. Vestibulocochlear (Auditory)
- 9. Glossopharyngeal
- 10. Vagas
- 11. Accessory
- 12. Hypoglossal
Name the cranial nerves in order (w/ types of nerve. no functions)
- 1. Olfactory: sensory nerve
- 2. Optic: sensory nerve
- 3. Oculomotor: motor nerve
- 4. Trochlear: motor nerve
- 5. Trigeminal: sensory & motor nerve
- 6. Abducens: motor nerve
- 7. Facial: sensory & motor nerve
- 8. Vestibulocochlear (Auditory): sensory nerve
- 9. Glossopharyngeal: sensory & motor nerve
- 10. Vagas: sensory & motor
- 11. Accessory: motor nerve
- 12. Hypoglossal: sensory & motor nerve
Name the Cranial Nerves in order (w/ function and type of nerve)
- 1. Olfactory: sensory nerve; deals w/ sense of smell
- 2. Optic: sensory nerve; sense of sight
- 3. Oculomotor: motor nerve; controls pupil dialation and eyelid
- 4. Trochlear: motor nerve; controls 4 out of 6 eye muscles
- 5. Trigeminal- sensory & motor nerve; sensory of touch on your face deals with chewing and the muscles in your nose
- 6. Abducens: motor nerve: controls other 2 of the 6 eye muscles; deals with eye rolling
- 7. Facial: sensory & motor nerve; controls tears and saliva and deals w/ taste
- 8. Vestibulocochlear (Auditory): sensory nerve: controls hearing
- 9. Glossopharyngeal: sensory & motor nerve; controls swallowing and the back of the tongue, bitter taste.
- 10. Vagas: sensory & motor nerve; vital center; deals with heart and lungs
- 11. Accessory: motor nerve; deals with trapezies muscles (traps) in your back. allows you to shrug and get chills in your spine
- 12. Hypoglossal: sensory & motor nerve; deals with the front of the tongue sweet taste
How many pairs of Spinal Nerves are there
31 pairs (peripheral nerves)
Picture of where cranial nerves are located
- Left: 6 7
- Right: 8 9
- Left: 10 11
- Right: 12
What is an EEG?
- EEG: Electroencephalogram
- measures the electrical activity of the brain
What is a Labotomy?
a removal of part of the brain
What is a CAT Scan?
- CAT Scan: Computed Axial Tomography
- computer assisted x-ray of the brain. Maps out parts of the brain and can take off certian parts so you can see deeper inside
What is a conditioned Reflex? Example?
conditioned reflex allows you to create a reflex. Pavlov had dogs and every time he fed them he would ring a bell and eventually, when he rang the bell the dogs would automatically start salivating
What is Instrumental Conditioning?
manipulating or doing something to create a wanted reaction. ex: training to do things fro rewards, giving kids candy for behaving
What is an MRI?
- MRI: Magnetic Resonance Imaging
- you go into this tube and a magnet goes around you, pulls up all your ions and then drops them back to map out your body. allows you to see organs and stuff inside the body without cutting someone open
- Restricitons: You can't move in it (takes a long time), you can't weigh over 300lbs, and you can't have any metal in your body.
Divisions of the Nervous System?
- CNS: central nervous system; brain and spinal cord
- PNS: peripheral nervous system; spinal nerves, sensory and motor nerves, everything outside brain and spinal cord
What are the two parts of the PNS?
- 1. Somativ Nervous System
- 2. Autonomic Nervous Sytem
What is the Somatic Nervous System?
- made up of special senses: sight, touch, smell, taste, hearing
- controls voluntary funtions
What is the Autonomic Nervous System?
- regulates the body's automatic involuntary functions: heart beat, secretions of glands, body temp, and stomach and intestine contractions
- broken into 2 systems
What are the two systems of the Autonomic Nervous System?
- 1. Sypathetic Sytem
- 2. Parasymmpathetic system
What is the Sympatheic System?
- originates in the spinal cord so the message is comming out
- acts as an emergency system in times of stress/danger
- called "fight or flight response"- you fight or run away
- increases your heart rate,decreases size of blood vessels, increases blood pressure to move O2 faster around the body, stimulates adrenaline, decreases blood flow to the digestive system (can cause you to puke)
What is the Parasympathetic System?
- Originates in the brain stem (midbrain, pons, medulla oblongata) controls normal everyday activities
- opposing sympathetic: decreases heart rate and blood pressure, decreases respiratory rate, increases parastalsys (movement of food through the GI Tract) increses digestive juices and saliva
- used when your relaxed ex: sleeping