Biology- MODULE 8

Homeostasis

The maintanence of a stable internal environment despite changes in the external environment

Negative feedback

A process in which a change in a system triggers a response that counteracts the original change, restoring stability

Positive Feedback

A process in which a change in a system triggers a response that amplifies the original change.

Receptor

A specialised cell or structure that detects a stimulus

Stimulus

A change in the internal or external environment that can be detected by receptors.

Effector

A muscle or gland that carries out a response to a stimulus

Type 1 diabetes

An autoimmune disease in which the bodys immune system destroys insulin producing beta cells in the pancreas.

Type 2 diabetes

A disorder in which body cells become resistant to insulin and/or insufficient insulin is produced

Neuron

A specialised nerve cell that transmits electrical impulses throughout the body

Sensory neuron

A neuron that carries impulses from receptors to the central nervous system.

Motor neuron

A neuron that carries impulses from the central nervous system to effectors.

Interneuron

A neuron located within the central nervous system that connects sensory neurons and motor neurons.

Synapse

The junction between two neurons where neurotransmitters transmit signals.

Neurotransmitters

A chemical messenger that transmits signals across a synapse.

Hormone

A chemical messenger produced by endocrine glands and transported in the blood to target cells.

Endocrine Gland

A gland that secretes hormones directly into the bloodstream.

Target cell

A cell that contains specific receptors for a particular hormone

Insulin

A hormone produced by the pancreas that lowers blood glucose concentration by increasing celluar glucose uptake.

Glucagon

A hormone produced by the pancreas that raises blood glucose concentration.

Antidiuretic hormone (ADH)

A hormone that regulates water balance by increasing water absorption in the kidneys.

Disease

A conditioning that impairs the normal functioning of an organism

Disorder

A disruption of normal structure or function within the body

Genetic disorder

A disorder caused by abnormalities in an indivuals genetic material

Autosomal dominant disorder

A genetic disorder that occurs when one copy of a dominate allele is present on an autosome

Autosomal recessive disorder

A genetic disorder that occurs only when two copies of a recessive allele are present on an autosome

Mutation

A permanent change in the DNA sequence of an organism

Gene therapy

A technique involving the introduction, removal or modification of genetic material to treat disease.

Epidemiology

The study of the distrubution, causes and control of diseases in populations

Incidence

The number of new cases of a disease occuring in a population during a given period of time.

Prevalance

The total number of cases of a disease in a population in a given time

Mortality

The number of deaths due to a disease in a population in a given time

Risk Factor

Any characteristics or exposure that increases the likelihood of developing a disease