The Nervous System and Brain
Ana Cendejas Period:7

Major Functions of Spinal Cord

Sensory-detects changes (stimuli) within body and outside the body

Integrative-It analyzes sensory information, stores some aspects and makes decisions regarding appropriate behavior's

Major Divisions of NS

Central Nervous System (CNS)-Receives incoming sensory information ,issue instructions,integration of information,thoughts, and emotions. Nerve impulses that influence effect-or organs begins in CNS.

Peripheral Nervous System-Spinal nerves carry impulses to and from spinal cord, and cranial nerves carry impulses to and from cranium.

  1. Sensory (afferent) Nerves- Relays information from skin,muscles, and glands to CNS

Major Parts of the Brain

Names of the Lobes of the Brain

Frontal Lobe-Part of the brain that controls emotional expressions,problem solving,memory,language,judgment, and sexual behavior's. It;s located near the forehead.

Parietal Lobe-Processes sensory information regarding the location of the parts of the body. It's located near the center of the brain.

Temporal Lobe-Controls memory,sensory input,language, and comprehension.It's located behind the ears.

Occipital Lobe-Controls vision, color determination, face recognition, and face recognition. It's located rear portion of the skull.

Diseases and Brain injuries

Structure of Neurons

Classifications of Neurons

Major parts and
functions of the spinal cord

Motor-It may respond to stimuli by initiating muscular contractions or glandular secretions

Spinal Cord- Connection between the brain and brainstem to the rest of the body

Cerebrum- Largest part of the brain and associated with higher mental function

Diencephalon- Processes sensory input and controls many homeostatic process

Brainstem- Coordinates and regulates visceral activities

Cerebellum- Coordinates muscular activity

Layers of meninges of the Brain

Dura Mater- The outer layer, tough, white dense connective tissue and contains many blood vessels

Arachnoid Mater- The middle layer, very thin, lacks blood vessels

Pia Mater- The inner layer, it covers every fold of the brain

Dendrite- portion of neuron that receives impulse and sends signals to the cell body

Cell body- Contains nucleus and other organelles is the metabolic center

Axon- The portion that conducts signal away from body cell

Myelin- Fatty substance that surrounds axon, and insulates signal

Node of Ranvier- Spaces between myelin and schwann cells

Synapse- The junction between two communicating neurons

Multipolar- Many dendrites and one axon

Bipolar- One dendrites and one axon (sensory)

Unipolar- Fused axon and dendrites (sensory)

Motor (efferent) Neuron- Carry instructions away from CNS to target or effector organs of the body

  1. Somatic- Senses and responds to external environment
  1. Automatic- Responds to internal environment

Anatomy of Spinal Cord

Two deep longitudinal grooves divide the cord into the right and left halves. White matter is a butterfly shaped core of gray matter housing interneurons and cell bodies. The gray matter divides the white matter into 3 regions anterior, lateral and posterior funiculi. The gray commissure is where fibers cross from side to side.

Nerve Coverings

Endoeurium- surrounds individual fibers within a nerve

Perineurium- Surrounds a fascicle

Epineurium- Surrounds the entire nerve

Fascicle- A group of nerve fibers

Action Potential

Resting Membrane Potential: Membrane at rest has polarized fewer potassium ions inside and more sodium ions outside

Stimulus begins depolarization-Strong stimulation or nerve impulse causes sodium ion gates to open. Then sodium ions rush into cell causing depolarization.

Threshold Potential- If a strong depolarization occurs, it reaches the threshold potential (-55mv).

Action Potential occurs- When the threshold is achieved it causes and action potential, where a nerve is transmitted.

Repolarization- Once repolarization begins K plus rushes out of neuron after Na plus rushes in.

Resting State- After depolarization stage the Na plus gates open, then close going into an inactive conformation until the repolarization goes to it's normal resting potential and is ready to repeat the process again.

Concussion- Shaking of the brain, no permanent damage, results of swelling

Contusion- Causes tissue destruction, permanent damage

Intracranial hemorrhage- Bleeding in the skull

Alzheimer, Parkinson disease and multiple sclerosis

Drugs that affect the brain

Heroine activates receptors in the brain. This causes greater amounts of dopamine to be released into reward system making an intense short lived rush

Ecstasy blocks the reuptake pumps for certain neurotransmitters and it increases their levels in synaptic gap and effects on the post synaptic neurons receptors

Tetrahydrocannabinol is the active ingredient in marijuana. It activates a specific receptor in the brain called cannabinoid. When it activates these receptors it interferes with the normal functioning of many areas of the brain

Methamphetamine causes the release of neurotransmitters dopamine, norepinephrine. The release of neurotransmitters activates the heart rate and increases the blood pressure

Reflex Arc

Sensory/ afferent neuron- sends signals to CNS

Synapse/ Interneuron Integration center- Connection between sensory neuron and motor efferent neuron

Sensory receptor- afferent nerve ending detects stimulus

Motor/ efferent neuron- delivers response to target organ

Effector- targets organ responds to signal

Automatic Nervous System

Controls involuntary responses

Somatic Nervous System

Controls voluntary movements