Unit 1 Topic 3,4- Biology

Central Nervous System

Consists of the brain and spinal cord

Peripheral Nervous System

The sensory and motor neurons that connect the central nervous system to the rest of the body

Somatic Nervous System

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

Autonomic Nervous System

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

Sympathetic Nervous System

The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body, conserving its energy

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.

Limbic System

Neural system located below the cerebral hemispheres; associated with emotions and drives

Neurons

Individual cells in the nervous system that receive, integrate, and transmit information.

Cell Body

Largest part of a typical neuron; contains the nucleus and much of the cytoplasm

Dendrites

A neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

Axon

The neuron extension that passes messages through its branches to other neurons or to muscles or glands

Myelin Sheath

A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

Terminal Button

The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron

Threshold

The level of stimulation required to trigger a neural impulse

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 central nervous system to the muscles and glands

Interneurons

Central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Action Potential

The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons

Acetylcholine

A neurotransmitter that enables learning and memory and also triggers muscle contraction

Dopamine

A neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal

Serotonin

Affects mood, hunger, sleep and arousal. Undersupply linked to depression.

Endorphins

"Morphine within"--natural, opiatelike neurotransmitters linked to pain control and to pleasure.

GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter. Undersupply linked to seizures, tremors, and insomnia.

Endocrine System

Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells.

Hormone

Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another

Pituitary Gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Adrenal Gland

A pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress.

Thyroid Gland

Produces hormones that regulate metabolism, body heat, and bone growth

Sex Glands

Ovaries and testes produce hormones to develop sexual characteristics and maintain reproductive organs

Genes

The biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein

Chromosome

A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins.

Heritability

The proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied.

Nature v. Nurture

The longstanding controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors

Identical Twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms

Fraternal Twins

Twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment.

Turner's Syndrome

A genetic defect in which affected women have only one X chromosome, causing developmental abnormalities and infertility.

Kleinfelter's Syndrome

Male with more than one X chromosome (XXY), little to no sperm, fertility treatment

Down Syndrome

A condition of mild to severe intellectual disability and associated physical disorders caused by an extra copy of chromosome 21

Tay-Sachs syndrome

Recessive trait that produces progressive loss of nervous function and death in a baby

Genotype

An organism's genetic makeup, or allele combinations.

Phenotype

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Dominiant gene

Gene which most likely indicates what features you have.

Recessive Gene

Gene that is hidden when the dominant gene is present

Albinism

Congenital hereditary condition characterized by partial or total lack of pigment in the skin, hair, and eyes

Phenylketonuria (PKU)

A disorder related to a defective recessive gene on chromosome 12 that prevents metabolism of phenylalanine

Huntington's disease

A human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20 years after the onset of symptoms.

Color-blindness

A variety of disorders marked by inability to distinguish some or all colors

Brain Stem

Connection to spinal cord. Filters information flow between peripheral nervous system and the rest of the brain.

Medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

Pons

A brain structure that relays information from the cerebellum to the rest of the brain

Reticular Formation

A nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal

Thalamus

The brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Hypothalamus

A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Amygdala

A limbic system structure involved in memory and emotion, particularly fear and aggression.

Hippocampus

A neural center located in the limbic system that helps process explicit memories for storage.

Cerebellum

The "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance

Right hemisphere

This half of the brain specializes in perception of physical environment, art, nonverbal communication, music & spiritual aspects. It receives information from and controls the opposite side of the body.

Left hemisphere

Controls the right side of the body; analytical, language, math

Occipital Lobe

A region of the cerebral cortex that processes visual information

Parietal Lobe

A region of the cerebral cortex whose functions include processing information about touch.

Frontal Lobe

A region of the cerebral cortex that has specialized areas for movement, abstract thinking, planning, memory, and judgement

Broca's Area

Controls language expression - an area, usually in the left frontal lobe, that directs the muscle movements involved in speech.

Temporal Lobe

An area on each hemisphere of the cerebral cortex near the temples that is the primary receiving area for auditory information

Wenicke's Area

Controls language reception - a brain area involved in language comprehension and expression; usually in the left temporal lobe

Association Areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking

Lesion

Tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue

EEG

An amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp.

MRI

A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain

CAT scan

A method of creating static images of the brain through computerized axial tomography

PET scan

A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task