Year 9 Science: The Nervous and Endocrine System

Comprehensive vocabulary flashcards covering the structure and function of the human nervous and endocrine systems, including brain anatomy, neuron structure, and homeostatic mechanisms.

Nervous System

The body's system that detects, interprets and coordinates a response to stimuli (both external and internal).

Central Nervous System (CNS)

Part of the nervous system that contains the brain and spinal cord.

Peripheral Nervous System (PNS)

Part of the nervous system that contains the nerves that branch off from the spinal cord.

Somatic Nervous System

Part of the peripheral nervous system that controls voluntary movement and reflex arcs.

Autonomic Nervous System

Part of the peripheral nervous system that controls involuntary body functions and self-regulatory control over internal muscles, organs, and glands.

Sympathetic Nervous System

A division of the autonomic nervous system that prepares the body for action, commonly known as the "fight, freeze, or flight" response.

Parasympathetic Nervous System

A division of the autonomic nervous system that calms the body and conserves energy, commonly known as the "rest and digest" response.

Stimulus

Any change in the internal or external environment that triggers a response.

Response

A reaction to a stimulus.

Receptor

A specialised cell or protein that detects stimuli in the internal or external environment.

Neuron

The basic cellular unit of the nervous system that communicates through electrochemical messages.

Dendrites

Branches of a neuron that receive incoming signals and are covered in receptor sites.

Soma

The neuron's cell body where normal cell functions occur; it contains the nucleus.

Axon

The long, cable-like fibre that carries electrical signals away from the cell body.

Myelin Sheath

Fatty insulation around the axon that speeds up nerve impulses.

Axon terminal

The end of an axon that releases neurotransmitters into the synapse.

Synapse

The microscopic gap between neurons over which neurotransmitters pass to stimulate the next neuron.

Neurotransmitter

A chemical messenger that carries signals across a synapse.

Action potential

An electrical impulse that travels along the length of a neuron.

Sensory neuron

A type of neuron that carries information from receptors to the Central Nervous System (CNS).

Interneuron

A type of neuron located in the CNS that connects and processes information between sensory and motor neurons.

Motor neuron

A type of neuron that carries commands from the interneurons in the CNS to muscles or glands (effectors).

Frontal lobe

Part of the brain that controls reasoning, planning, movement, and speech.

Parietal lobe

Part of the brain that processes touch, temperature, pain, and spatial awareness.

Temporal lobe

Part of the brain that processes hearing, memory, facial recognition, and language.

Occipital lobe

Part of the brain responsible for processing visual information.

Hypothalamus

A brain structure that maintains homeostasis and controls the pituitary gland.

Pituitary gland

Known as the "master gland," it releases hormones that control other endocrine glands.

Cerebellum

Part of the brain that coordinates balance, posture, and voluntary movement.

Medulla

Part of the brainstem that controls vital involuntary functions such as breathing and heart rate.

Cerebrum

The largest part of the brain responsible for higher-order thinking, memory, sensation, and voluntary movement.

Reflex arc

The neural pathway that produces a rapid, automatic reflex response without immediate involvement of the brain.

MRI (Magnetic Resonance Imaging)

A brain imaging technique that produces detailed images of brain structure.

fMRI (functional MRI)

A technique that measures changes in blood flow and oxygen levels to show brain activity.

EEG (Electroencephalogram)

A test that records the brain's electrical activity using electrodes placed on the scalp.

Homeostasis

The maintenance of a relatively stable internal environment despite changes in the external or internal environment.

Hormones

Chemical messengers released by endocrine glands into the bloodstream that regulate body functions.

Endocrine System

A system of glands that secrete hormones to coordinate body functions with a slower, longer-lasting response compared to the nervous system.

Lock and Key Model

A model where a specific neurotransmitter or hormone (key) only fits into a specific receptor (lock) with a complementary shape.

Effector

A muscle or gland that carries out a response to a signal from the control centre.

Negative Feedback

A response mechanism in which the effect of the response reverses the original stimulus to return a variable to its set point.

Insulin

A hormone secreted by Beta ($\beta$) cells in the pancreas that decreases blood glucose levels.

Glucagon

A hormone secreted by Alpha (alpa) cells in the pancreas that increases blood glucose levels by triggering the liver to convert glycogen to glucose.

Adrenaline

A hormone produced by the adrenal glands that travels in the bloodstream to target cells in various organs to prepare the body for action.

Normal Blood Glucose Range

The homeostatic level of glucose in the blood, typically between $4-8\,mmol/L$.