Coordination and Control - Vocabulary Flashcards

Key vocabulary terms and concise definitions covering coordination, nervous and hormonal regulation, plant hormones, and related physiological concepts from the notes.

Coordination (biology)

Integration of activities of body parts to respond to stimuli and maintain organism function.

Stimulus

Any internal or external change that elicits a response from an organism.

Plant Growth Regulators

Substances that influence growth, development, and responses in plants (e.g., auxins, gibberellins, cytokinins, ABA, ethene).

Auxins (IAA)

Plant hormones that promote cell elongation behind the shoot tip, regulate growth, and establish apical dominance.

IAA (Indole-3-acetic acid)

Natural auxin that stimulates root formation and leaf/ shoot growth at appropriate concentrations.

Synthetic Auxins (e.g., NAA)

Man-made auxins used commercially for rooting, fruit set, and weed control; often more stable than natural IAA.

2,4-D

A synthetic auxin used as a selective herbicide; kills broad-leaved weeds.

Gibberellins

Plant hormones that promote cell enlargement/division, flowering in some conditions, and breaking dormancy.

Cytokinins

Plant hormones that stimulate cell division, shoot growth, and delay leaf senescence.

Abscisic Acid (ABA)

Plant hormone that inhibits growth, promotes seed dormancy, and helps close stomata during stress.

Ethene (Ethylene)

Gaseous plant hormone that inhibits stem growth and promotes fruit ripening and dormancy release.

Circadian Rhythm

Biological rhythm of about 24 hours tied to the day-night cycle.

Circannual Rhythm

Biological rhythm with a ~365-day cycle (annual).

Autonomic Plant Movements

Movement of plant organs driven by growth responses, not organismal locomotion.

Paratonic Movements

Plant movements modified by external stimuli (growth-based responses).

Receptors

Specialized cells or endings that detect environmental changes; categorized by modality.

Chemoreceptors

Receptors that detect chemical stimuli such as odors, tastes, or blood gases.

Mechanoreceptors

Receptors responsive to mechanical stimuli like touch and pressure.

Photoreceptors

Receptors that detect light (e.g., rods and cones in eyes).

Thermoreceptors

Receptors that detect temperature changes.

Nociceptors

Pain receptors that detect damaging or potentially harmful stimuli.

Neuron

Nervous system cell that transmits electrical and chemical signals.

Sensory Neuron

Neuron that carries impulses from receptors to the central nervous system.

Interneurons/Association Neurons

Neurons within the CNS that connect sensory and motor neurons.

Motor Neuron

Neuron that transmits impulses from the CNS to effectors (muscles or glands).

Dendrite

Neuron branch that carries impulses toward the cell body.

Axon

Neuron fiber that conducts impulses away from the cell body.

Resting Membrane Potential

Electrical potential across the neuron's membrane at rest (approximately −70 mV).

Action Potential

Brief reversal of membrane potential that propagates along the neuron as an electrical impulse.

Saltatory Conduction

Jumping of an action potential between nodes of Ranvier in myelinated neurons.

Synapse

Gap between neurons where neurotransmitters transmit signals to the next neuron.

Neurotransmitter

Chemical messengers released at synapses (e.g., acetylcholine, adrenaline, noradrenaline, serotonin, dopamine).

Reflex Arc

Neural pathway for a reflex: receptor → sensory neuron → association neuron → motor neuron → effector.

Central Nervous System (CNS)

Brain and spinal cord; processes information and coordinates responses.

Peripheral Nervous System (PNS)

Nerves and ganglia outside the CNS that transmit signals between CNS and the body.

Somatic Nervous System

PNS subdivision that controls voluntary movements via skeletal muscles.

Autonomic Nervous System

PNS subdivision controlling involuntary functions; includes sympathetic and parasympathetic divisions.

Sympathetic Division

Part of the autonomic system that prepares the body for stress ('fight or flight').

Parasympathetic Division

Part of the autonomic system that promotes 'rest and digest' activities.

Hypothalamus-Pituitary Axis

Hypothalamic releasing/inhibiting hormones regulate anterior pituitary tropic hormones; posterior pituitary stores/releases oxytocin and ADH.

Master Gland (Anterior Pituitary)

Anterior pituitary gland that secretes growth hormone, TSH, ACTH, FSH, LH, and prolactin.

Thyroxine (T4) / T3

Thyroid hormones that regulate metabolism; iodine-containing; deficiencies/excess cause metabolic disorders.

Calcitonin

Thyroid hormone that lowers blood calcium levels.

Parathormone (PTH)

Parathyroid hormone that raises blood calcium and regulates calcium-phosphate balance.

Islets of Langerhans

Pancreatic endocrine tissue containing insulin-producing beta cells and glucagon-producing alpha cells.

Insulin

Hormone that lowers blood glucose by promoting uptake and storage as glycogen or fat.

Glucagon

Hormone that raises blood glucose by promoting glycogen breakdown and glucose release.

Adrenal Glands

Glands atop the kidneys with cortex and medulla producing steroids and catecholamines.

Adrenaline (Epinephrine)

Hormone from adrenal medulla that increases heart rate and energy release during stress.

Noradrenaline (Norepinephrine)

Adrenal medulla hormone that constricts some vessels and raises blood pressure.

Cortisol

Glucocorticoid from adrenal cortex; raises blood glucose during stress and influences metabolism.

Aldosterone

Mineralocorticoid from adrenal cortex; regulates Na+/K+ balance and fluid homeostasis.

Feedback Mechanism

Regulatory loop where the product of a process feeds back to adjust the process itself.