Control and Coordination – Nervous System and Hormonal Regulation

Forty vocabulary flashcards covering key terms in nervous control, reflexes, plant tropisms, and hormonal coordination in plants and animals.

Control and Coordination

Integrated processes by which organisms detect environmental changes and produce appropriate responses using nervous and hormonal systems.

Nervous Tissue

Specialised tissue composed of neurons that conducts information rapidly through electrical impulses.

Neuron

Functional nerve cell with dendrites, cell body and axon that transmits electrical impulses.

Dendrite

Branched projection of a neuron that receives signals from receptors or other neurons.

Axon

Long fibre of a neuron that carries electrical impulses away from the cell body toward synapses.

Synapse

Junction between two neurons (or a neuron and another cell) where impulses pass via neurotransmitter chemicals.

Receptor

Specialised sensory cell ending that detects specific environmental stimuli such as light, sound, taste or heat.

Reflex Action

Fast, automatic response to a stimulus that occurs without conscious thought.

Reflex Arc

Neural pathway linking receptor to effector through the spinal cord to produce a reflex action.

Central Nervous System (CNS)

Brain and spinal cord, the main coordinating centre of the body.

Peripheral Nervous System (PNS)

Cranial and spinal nerves that connect the CNS to the rest of the body.

Fore-brain

Anterior brain region responsible for thinking, sensory interpretation and voluntary actions.

Mid-brain

Brain region that relays information and controls some involuntary actions like pupil reflexes.

Hind-brain

Posterior brain part including cerebellum and medulla that controls balance and vital involuntary functions.

Cerebellum

Part of hind-brain that coordinates precision, posture and balance of voluntary movements.

Medulla

Hind-brain region that regulates involuntary actions such as heartbeat, breathing and vomiting.

Spinal Cord

Long nerve bundle within the vertebral column that conducts impulses to and from the brain and forms reflex arcs.

Voluntary Action

Movement performed under conscious control, e.g., writing or walking.

Involuntary Action

Movement not under conscious control, e.g., heartbeat or digestion.

Neuromuscular Junction

Synapse where a motor neuron communicates with a muscle fibre to initiate contraction.

Muscle Fibre

Elongated muscle cell that contracts by rearrangement of special proteins in response to nerve impulses.

Plant Tropism

Directional growth movement of a plant part toward or away from a stimulus.

Phototropism

Growth response of plant shoots toward light and roots away from light.

Geotropism

Growth response of plant parts to gravity; roots grow downward, shoots upward.

Hydrotropism

Directional growth of plant roots toward moisture.

Chemotropism

Growth movement toward or away from specific chemicals, e.g., pollen tube growing toward ovule.

Auxin

Plant hormone produced at shoot tips that promotes cell elongation and phototropic bending.

Gibberellin

Plant hormone that stimulates stem elongation and overall growth.

Cytokinin

Plant hormone that promotes cell division, abundant in fruits and seeds.

Abscisic Acid

Plant hormone that inhibits growth and causes leaf wilting; involved in stress responses.

Hormone

Chemical messenger secreted in tiny amounts that travels to target cells to regulate physiology.

Endocrine Gland

Ductless gland that secretes hormones directly into the bloodstream.

Adrenaline

Fight-or-flight hormone from adrenal glands that increases heartbeat, breathing rate and redirects blood to muscles.

Thyroxin

Iodine-containing hormone from thyroid gland that regulates metabolism of carbohydrates, proteins and fats.

Growth Hormone

Pituitary hormone that stimulates overall growth and development; deficiency causes dwarfism.

Insulin

Pancreatic hormone that lowers blood glucose levels by promoting uptake and storage of sugar.

Testosterone

Male sex hormone from testes that controls development of male reproductive organs and secondary sexual traits.

Oestrogen

Female sex hormone from ovaries that regulates development of female reproductive organs and menstrual cycle.

Feedback Mechanism

Self-regulating system in which the effects of a hormone influence its own secretion level.

Iodised Salt

Table salt fortified with iodine to prevent iodine deficiency and ensure proper thyroxin synthesis.