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Sarah Heard pd6 - Nervous System (Drugs that affect the brain…
Sarah Heard pd6 - Nervous System
Functions of the Nervous System
Motor functions
It may respond to stimuli by initiating muscular contractions or glandular secretions
integrative function
Analyzes sensory information, stores some aspects, and makes decisions regarding appropriate behaviors
Sensory functions
defects changes with the body and outside the body
Major parts of brain
Diencephalon
Function: Relays sensory information between brain regions and controls many
Made of thalamus and hypothalamus
Cerebrum
largest portion
Function: control senses, thoughts and movements
Cerebellum
Sulci: Grooves
Gyri: Convolutions
Function: Receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements
Vermisse: a narrow, worm shaped structure in between both sides of the cerebellum
Brain stem
Function: Controls the flow of messages between the brain and the rest of the body
Made of; Medulla oblongata, pons and midbrain
Functions of lobes
Frontal Lobe
Motor function, problem solving, memory language, and impulse control
Temporal Lobe
Primary auditory perception
Occipital Lobe
Visual processing center of the mammalian brain containing most of the visual cortex
Parietal
processing sensory information regarding the location of parts of the body and interpreting visual information
Divisions and Subdivisions of the nervous system
Central Nervous System
thoughts and emotions are generated
memories are formed and stored
Information is integrated
Most nerve impulses that influence effector organs begin in CNS
Peripheral Nervous System
sensory/ afferent neurons
carry information form body toward CNS
motor/ efferent neurons
carry instructions away form CNS to target or effector organs of body
structures and functions of a neuron
Functions
Process and transmit information
Structure
Axon
Start a single fiber, but may give off branches called collateral axon
Cell body
Contains nucleus and other organelles
Dendrites
Receiving portions, short, tapered and highly branched
Classification of neurons
Motor of efferent neurons
Transmit motor nerve impulses from CNS to effectors
Interneurons: multipolar neurons in CNS that form links between other neurons
Sensory of afferent neurons
Have specialized receptor ends at tips of dendrites or the dendrites are in contact with specialized receptor cells in skin or sense organs
Transmits sensory impulses toward CNS
Bipolar
One main dendrite and one axon
usually found in special sense organs
Multipolar
Several dendrites and one axon
neurons of CNS are mostly this type
Unipolar
just one process, and are always sensory neurons
Axon terminals are in CNS & cell bodies in ganglia
the layers of the meninges
Pia Mate
Subarachnoid space: area between arachnoid and pia mater; filled with cerebrospinal fluid
Follows contours of brain and spinal cord
Innermost, nearly transparent layer; has many nerves and blood vessels
Dura Mate
Meningitis: inflammation of meninges
Dense, irregular , C.T. with many blood vessels and nerves
Attached to periosteum
Arachnoid Mater
Spiderweb-like collagen and elastic fiber
Thin membrane that lacks blood vessels
Subdural space: fluid filled area between dura and subarachnoid maters
Major parts and
functions of the spinal cord
White matter tracts serve as information highways to and from brain
Gray matter receives and integrates information highways to and from brain
Action potential
If strong enough, depolarization occurs, threshold potential is reached and impulse is set down axon
Nerve impulse is transmitted during action potential
K+ rushes out of neuron after Na+ rush in, which is cause a re-polarization of the membrane back to resting potential
Strong enough simulation or nerve impulse causes Na+ gates to open, then Na+ rush into cells causing depolarization.
Drugs that affect the brain
Methamphetamine
Cause mental alter ness and increases energy
Marijuana
Causes peaceful and euphoric sensation in the user. After the sensation passes, and user feels depresses or sleepy
Herion
Causes a rush of pleasure in the user that is usually fallowed by several hours of drowsiness
GHB and Rohypnol
Causes death, seizures, loss of consciousness and a coma
Alcohol
Which causes loss of motor coordination and impairs reasoning, balance, speech, reaction time and judgement
Anabolic Steriods
The can cause psychological dependence that is driven by perceived self-image, competition or pressure from others
Cocaine
Cause disturbances in heart rhythm, nausea, respiratory failure, strokes and seizures
Hallucinogens
Drugs that cause hallucinations, distortions in perception of reality and time
inhalants
chemicals that can be inhaled to get an immediate high. Causes permanent brain damage death
MDMA
Causes panic attacks, loss of consciousness , and seizures
Nicotine
Produces a calm or soothing effect
Diseases associated with the brain
Alzheimer's Disease
slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks of daily living
Dementias
involves memory loss and decline in intellectual functioning that is severe enough to interfere with an individual’s ability to perform routine tasks
Brain Cancer
cancerous cells have spread to the brain from a tumor located elsewhere in the body
Mental Disorders
disrupt a person’s thinking, feeling, mood, daily functioning and ability to relate to others
Parkinson's
leads to shaking (tremors) and difficulty with walking, movement, and coordination
Stroke
Brain cells deprived of blood and oxygen can die, causing permanent damage resulting in weakness or paralysis of an arm or leg or problems with speech
Divisions of the PNS of the body
Automatic Nervous System
brings info from receptors internal organs to CNS & motor neurons to smooth muscle, cardiac muscle and glands
involuntary
Sympathetic Nervous System
Emergancy or non- normal situations
Somatic Nervous System
brings info form skin, special sense, body wall and limbs to CNS, & motor neurons to skeletal muscles
Voluntary
Parasympathetic Nervous System
Normal everyday situations
Anatomy of the spinal cord
Conus medlaris
end of cord
Cervical enlargement
nerves to & form upper limbs
31 pairs of spinal nerves
Lumbar enlargement
nerves & form lower limbs
Extends from medulla oblongata and ends at second lumbar vertebrae in adults
Cauda equina: horse tail
cord divides into nerves that leave at lower levels
Connection between the brain and brainstem to the rest of the body
Coverings
CNS
Bone- Cranium and vertebral column
Meninges
three connective tissue layers
arachnoid
"spiderweb" middle
pia mater
inner
dura mater
most outer
Endoneuronrium
surrounds individual neuron
Perneurium
Surrounds fascicles
Epinerium
surrounds entire nerve
Neurotransmitters
Needs to be removed or will influence nerve indefinitely
Needs to be removed or will influence nerve indefinitely
Some degraded by enzymes
Some reuptake into cells
Synaptic end bulbs may contain 2 or 3 different neurotransmitters