Control and Coordination – Vocabulary Flashcards (Nervous System and Hormones)

Key terms and definitions from the notes on nervous system, brain function, reflex actions, and hormonal (endocrine) coordination in plants and animals.

Neuron

Nerve cell; the basic unit of the nervous system that transmits information via electrical impulses and chemical signals at synapses.

Receptors

Specialised sensory endings that detect stimuli (touch, taste, smell, etc.) and convert them into electrical signals.

Gustatory receptors

Taste-detecting receptors located in taste buds; respond to chemicals in food.

Olfactory receptors

Smell-detecting receptors in the nose; detect odour molecules.

Dendrite

Part of a neuron that receives impulses and conducts them toward the cell body.

Axon

Long extension of a neuron that carries impulses away from the cell body toward the synapse.

Synapse

Junction between neurons where neurotransmitters cross the gap to pass signals to the next neuron.

Neuromuscular junction

Synapse between a motor neuron and a muscle cell that triggers muscle contraction.

Nervous system

Network of nerves that coordinates body activities through electrical impulses.

Central nervous system (CNS)

Brain and spinal cord; the main processing and control center.

Peripheral nervous system (PNS)

Nerves outside the CNS that connect it to muscles and sense organs.

Reflex arc

Neural pathway for a reflex action, often bypassing the brain for a quicker response.

Brain

Central organ of the nervous system that processes information and controls actions.

Forebrain

Front part of the brain involved in thinking, processing senses, and association.

Midbrain

Middle region of the brain; part of the CNS involved in relay and coordination.

Hindbrain

Lower part of the brain; includes cerebellum and medulla; controls involuntary actions.

Cerebellum

Region of the hindbrain that coordinates movement, balance, and posture.

Medulla

Lower brain region that controls involuntary actions like heart rate and breathing.

Hypothalamus

Brain region regulating endocrine output; links nervous and hormonal systems; also thermoregulation.

Pituitary gland

Master endocrine gland that secretes several hormones; regulated by the hypothalamus.

Thyroxin

Hormone produced by the thyroid; regulates metabolism and growth.

Iodine

Element essential for thyroxin synthesis; deficiency can cause goitre.

Growth hormone

Pituitary hormone that promotes growth of body tissues.

Insulin

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

Adrenaline

Hormone from adrenal glands; triggers fight-or-flight responses (increases heart rate, respiration).

Endocrine system

Chemical coordination system using hormones released into the bloodstream.

Hormones

Chemical signals produced by glands that travel through the blood to regulate body functions.

Releasing hormones

Hypothalamic hormones that stimulate the pituitary to release its hormones.

Auxin

Plant hormone produced at the shoot tip; causes cell elongation and bending toward light.

Gibberellins

Plant hormones that promote stem growth and development.

Cytokinins

Plant hormones that promote cell division and growth.

Abscisic acid

Plant hormone that inhibits growth and can cause wilting under stress.

Tropism

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

Phototropism

Growth toward light; shoots bend toward light, roots bend away.

Geotropism

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

Hydrotropism

Growth toward water.

Chemotropism

Growth toward chemicals (e.g., pollen tubes toward ovules)

Endocrine glands

Glands such as thyroid, pituitary, adrenal, pancreas, testes, ovaries, hypothalamus that secrete hormones.

Feedback mechanism

Regulatory loop where hormone levels regulate their own production to maintain balance.

Hormone receptors

Molecules on target cells that detect and respond to specific hormones.