Bio - Ch 35 Nervous System

Impulses

The messages carried by the nervous system are electrical signals called impulses

What is the difference between grey matter and white matter

The outer layer of the cerebrum is called the cerebral cortex and consists of grey matter which consists mainly of densely packed nerve cell bodies. The inner layer of the cerebrum consists of white matter, which is made up of bundles of axons with myelin sheaths

What happens when the nerve senses that the core temperature has dropped below 35 C?

The hypothalamus produces chemical that signals cells throughout the body to speed up their activities. Heat is produced by this increase in cellular activity

How does a reflex arc work?

The peripheral nervous system transmits impulses from sense organs to the CNS and back to muscles or glands.

Neuron

The cells that transmit impulses

What happens when the nerve system senses that the core temperature gone to high above 35 C?

The hypothalamus slows down cellular activities, minimizing the production of heat

Threshold

The level of stimulation required to trigger a neural impulse

What do the eleven organ systems do as a whole?

The eleven organ systems have a different set of functions, but they all work together, to maintain homeostasis

retina

The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.

Cells

Basic unit of life

What are the five general categories of sensory receptors?

pain receptors, thermorereceptors, mechanoreceptors, chemoreceptors, and photoreceptors

How does a moving impulse work?

1.) At Rest 2.) At the leading edge of the impulse, gates in the sodium channels open. The membrane becomes more permeable to Na+ ions 3.) As the action potential passes, gates in the potassium channels open, allowing K+ ions to flow out and restoring negative potential inside the axon 4.) The action potential continues to move along the axon

Cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

Stimulant

A drug that increases the action of the central nervous system, the heart, and other organs

Fetal Alcohol Syndrome

A group of birth defects caused by the effects of alcohol on an unborn child

Organ Systems

A group of organs that work together in performing vital body functions.

Addiction

A physiological or psychological dependence on a drug

Reflex Arc

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement.

Reflex

A simple, automatic, inborn response to a sensory stimulus, such as the knee-jerk response.

Organs

A structure consisting of several tissues adapted as a group to perform specific functions.

Somatic Nervous System

A subdivision of the peripheral nervous system. Enables voluntary actions to be undertaken due to its control of skeletal muscles

Myelin Sheath

Axon is surrounded by a clear membrane known as the Myelin Sheath.

Hypothalamus

Brain structure that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature

Thalamus

Brain structure that receives messages from the sense organs and relays the information to the proper region of the cerebrum for further processing

cones

Color vision

Depressants

Drugs that reduce neural activity and slow body functions.

How do Stimulants affect our body?

Increase heart rate, blood pressure, and breathing rate. In addition, stimulants increase the release of neurotransmitters at some synapses in the brain

Cerebrum

Largest part of brain, associated with higher order functioning including control of voluntary behaviour, e.g. Thinking, planning, perceiving, understanding language.

Synapse

Location at which a neuron can transfer an impulse to another cell

Axon

Long fiber that carries impulses away from the cell body. Axon ends in a series of small swellings called axon terminals, located some distance from the cell body.

What are the eleven organ systems?

Nervous System, Integumentary System, Respiratory System, Digestive System, Excretory System, Skeletal System, Muscular System, Circulatory System, Endocrine System, Reproductive System, Immune System

Sensory Receptors

Neurons that are specialized to detect a stimulus such as light, pressure, or heat

Sensory Neurons

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

Motor neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

rods

Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond.

How do depressants affect our body?

Slow down heart rate and breathing rate, lower blood pressure, relax muscles, and relieve tension

Dendrites

Spreading out from the cell body are short, branched extensions called dendrites. Dendrites carry impulses from the environment or from other neurons toward the cell body

Pupil

The adjustable opening in the center of the eye through which light enters.

Homeostasis

The process by which organisms keep internal conditions relatively constant despite changes in external environments. Homeostasis in the body is maintained by feedback loops

How does a neuron maintain resting potential?

The sodium-potassium pump in the neuron cell membrane uses the energy of ATP to pump Na+ out of the cell and, at the same time to pump K+ in. This ongoing process maintains resting potential.

lens

The transparent structure behind the pupil that changes shape to help focus images on the retina.

menings

Three layers of connective tissue membrane that protect the brain and spinal cord

What happens when two neurons are joined together?

When an impulse reaches the end of the axon of one neuron, neurotransmitters are released into the synaptic cleft. The neurotransmitters blind to receptors on the membrane of an adjacent dendrite

Alcohol

a depressant that slows down the rate at which the CSN functions

Marijuana

a drug, often smoked, whose effects include euphoria, impairment of judgment and concentration and occasionally hallucinations; rarely reported as addictive

Muscle Tissue

along with bones, enables the body to move

drug

any substance other than food that changes the natural structure or function of the body

Cerebrospinal Fluid

bathes the brain and spinal cord and acts as a shock absorber that protects the CNS

Cocaine

causes the sudden release in the brain of a neurotransmitter called dopamine (Stimulant)

Specialized Cells

cells uniquely suited to perform a particular function

What are the levels of organization in a multicellular organism including tissues, organ systems, cells, and organs?

cells, tissues, organs, and organ systems

Neurotransmitters

chemicals used by a neuron to transmit an impulse across a synapses to another cell

Hypothalamus

contains nerve cells that monitor both the temperature of the skin at the surface of the body and the temperature of organs in the body's core

What does the neuron system do?

controls and coordinates functions throughout the body and responds to internal and external stimuli

The cerebellum

coordinates balance and body movements

Thermore Recep

detect variations in temeratutre

Resting Potential

electrical charge across the cell membrane of a resting neuron

What are the four lobes the brain is separated into?

frontal, parietal, temporal, occipital

Epithelial Tissues

glands and tissues that cover interior and exterior body surfaces

What two functions does the human ear have?

hearing and detecting positional changes associated with movement

What is the CNS

it is the control center of the body

Opiates

mimic natural chemcials in the brain known as endorphins, which normally help to overcome sensations of pain

Feedback Inhabitation

or negative feedback, is the process in which a stimulus produces a response that opposes the original stimulus (Like an automatic thermostat)

Connective Tissues

provides support for the body and connects its parts

What does the central nervous system do?

relays messages, processes information, and analyzes information

Pain Recep

respond to chemicals released by damaged cells

Action Potential

reversal of charges, from negative to positive, also called a nerve impulse

Chemo recp

sensative to chemicals in external enviornments

photo recep

sensative to light

Mechanore Recep

sensative to touch, pressure, stretching of muscles, sound, and motion

What can the peripheral nervous system be divided into?

sensory division and motor division

Taste buds

sensory organs that contain the receptors for taste

What are the three types of neurons?

sensory, motor, interneuorn

What is the motor division further divided into?

somatic and autonomtic nervous system

Brain Stem

structure that connects the brain and spinal cord; includes the medulla oblongata and the pons. Each of these regions regulates the flow of info between the brain and the rest of the body

What does the CNS consist of

the brain and spinal cord

Drug Abuse

the intentional improper or unsafe use of a drug

Cell body

the largest part of a typical neuron - contains nucleus and much of the cytoplasm

Automatic Nervous System

the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.

Semicircular Canals

three canals within the inner ear that contain specialized receptor cells that generate nerve impulses with body movement

What does the sensory division do?

transmits impulses from sense organs to the central nervous system

What does the motor division do?

transmits impulses from the central nervous system to the muscles or glands

Nervous Tissue

transmits nerve impulses throughout the body

A neuron remains in its resting state until what?

until it receives a stimulus large enough to start a nerve impulse. The impulse causes a movement of ions across the cell membrane.

When does an impulse begin?

when a neuron is stimulated by another neuron or by the environment