Control and Coordination (Science, Chapter 6)

Vocabulary flashcards covering key terms related to nervous and hormonal control, reflexes, brain regions, and plant responses from the notes.

Neuron

A nerve cell that conducts electrical impulses; the basic unit of the nervous system.

Dendrite

The branched extension of a neuron that receives information from other neurons or receptors.

Axon

The long fiber of a neuron that transmits impulses away from the cell body to other neurons, muscles, or glands.

Synapse

The junction between two neurons where a chemical signal (neurotransmitter) crosses the gap to pass the impulse.

Receptor

A sensory cell or part of a cell that detects a stimulus (e.g., gustatory receptors for taste, olfactory receptors for smell).

Sense organ

An organ containing receptors (e.g., eye, ear, nose, tongue) that detects stimuli.

Reflex arc

A neural pathway for a reflex action, usually involving the spinal cord, enabling a rapid, automatic response.

Central nervous system (CNS)

Brain and spinal cord; the main coordinating centers that receive, process, and decide responses.

Peripheral nervous system (PNS)

Nerves outside the CNS (cranial and spinal nerves) that connect the CNS to the rest of the body.

Fore-brain

The main thinking part of the brain; includes areas for sensory reception and interpretation.

Hind-brain

Part of the brain that contains the cerebellum and medulla, important for involuntary actions and coordination.

Cerebellum

Part of the hind-brain responsible for precision of voluntary actions and balance.

Medulla

Part of the hind-brain that controls involuntary actions like breathing, heart rate, and vomiting.

Hypothalamus

Brain region that regulates the release of many hormones, often via releasing factors.

Pituitary gland

Master endocrine gland that secretes various hormones, including growth hormone, often controlled by hypothalamus.

Adrenaline

Hormone released into the blood that prepares the body for ‘fight or flight’ by increasing heart rate and redirecting blood flow.

Thyroxin (Thyroxine)

Thyroid hormone that regulates metabolism and is essential for growth; its production requires iodine.

Iodine

Element essential for thyroid hormone (thyroxin) synthesis; deficiency can cause goitre.

Growth hormone

Hormone from the pituitary that stimulates growth and development of the body.

Insulin

Hormone produced by the pancreas that regulates blood glucose levels.

Tropism

Directional growth response of a plant toward or away from a stimulus.

Phototropism

Growth or movement of a plant toward light (commonly shoots bend toward light).

Geotropism

Growth response to gravity; shoots typically grow upward and roots downward.

Auxin

Plant hormone produced at the shoot tip that promotes cell elongation and drives tropic bending toward light.

Gibberellins

Plant hormones that promote stem growth and elongation.

Cytokinins

Plant hormones that promote cell division and growth in rapidly dividing tissues.

Abscisic acid

Plant hormone that inhibits growth and can induce wilting during stress.

Sensitive plant (Mimosa/pod)

Plant that folds its leaves quickly in response to touch; movement occurs without nervous or muscle tissue.

Hormone

Chemical signal produced by endocrine glands that travels through the bloodstream to act on distant target tissues.

Negative feedback

Regulatory mechanism where the product or effect reduces the original stimulus, helping maintain balance (e.g., insulin release adjusted as blood sugar changes).