NERVOUS SYSTEM ANATOMY & physiology
Parts of the brain Frontal lobe- conscious thought, behavior, emotion, planning, personality, organizing, problem solving, most uniquely human of all brain structure. Front of brain Parietal: integrations of sensory information, perception, arithmetic, spelling, manipulation. Middle top of brain Temporal: smell, sound, processing of complex stimuli (faces/senses/memory/understanding language). Temple region
Parts of the brain Occipital: sense of sight. Back of brain Cerebellum: little brain, balance, coordination, muscular movement, timing, body position Brain stem: pons and medulla oblongata, relays signals between brain and spinal cord, heart rate, breathing rate, blood pressure Hypothalamus: integration center for autonomic NS, controls endocrine system, body temperature, water balance, sleep-wake pattern, food intake, behavioral responses with emotion
Functions Sensory: Monitor internal and external environment with receptors Integration: interpret sensory information (processing and higher order functions) Motor: respond to information through stimulation of effectors Muscle contraction Glands secretion
Divisions of nervous system Central: brain and spinal cord Peripheral: all tissues outside of CNS (sensory input and motor output), includes somatic and autonomic NS
TISSUE Neurons: excitable cells, transmit electrical signals 30,000 neurons can fit on a pinhead Neurons do not touch→ gap is the synapse (messages sent across gap by neurotransmitters) Can excite the next neuron or inhibit Can live for a lifetime and don’t divide High metabolic rate, constantly need oxygen and glucose, die within a few minutes without oxygen 100 billion in brain and 1 billion in spinal cord
nEURONS Sensory (afferent) toward CNS (skin and muscles), unipolar and bipolar Motor (efferent) from CNS to muscles/gland, multipolar
Neuroglia AKA glial cells- supporting cells CNS: astrocytes (star, common, metabolism, create blood-brain barrier, monitor interstitial fluid, secrete chemicals for embryological development, stimulate formation of scar tissue), oligodendrocytes (produce myelin), microglial (macrophages), ependymal (helps circulate cerebrospinal fluid, cilia, lines CNS and spinal cord) PNS: Schwann, satellite
INTERNEURONS 99% of all neurons Grey matter: receive sensory information, direct information into a region of CNS, initiate appropriate motor responses White matter: transmit information (sensory and motor) from 1 region of CNS to another
SYNAPSE Electrical current travels down the axon: enough electrical current in brain to power flashlight Vesicles with chemicals move toward membrane Chemical released and diffuse toward next cell Chemical opens up transport proteins and allow signal to go to next cell
FUN FACTS: BRAIN & cns Brain Mass of 100 billion neurons, learning occurs more and stronger as connections are made with neurons CNS Cerebrum Largest part, responsible for thought/senses/language/memory (not a snapshot, must be put together from information stored in other parts of the brain Cerebellum: muscle coordination/balance/posture Brain stem: breathing/swallowing/heart/blood pressure Spinal cord: column of nerves protected by vertebrae, conduct impulses between brain and body, 268 mph
pns Neurons that go from brain/spine to rest of body Sensory nerves: from body to brain (pain, temperature, pressure) Motor nerves: from brain to body (response)
What Changes Neurons and Connections? Accidents- physical injury of neurons concussion - temporary disturbance of brain's ability to function to due to a hit in the head Drugs/alcohol- bind to important receptors on neuron and repeated binding can cause neuron death Disease See disease chart