Biology: System Integration, Brain Functions, and Physiological Responses

Vocabulary flashcards focusing on system integration, nervous and endocrine signaling, brain regions, receptors, homeostatic controls, and plant growth responses.

System integration

A necessary process in living systems where coordination is needed for important parts of a system to collectively perform an overall function.

Cells

The basic unit of life.

Tissues

Groups of similar cells performing one function.

Organs

Different tissues working together for a specific function.

Body systems

Groups of organs carrying out broad functions, such as the digestive or nervous system.

Nervous system

A signaling system using electrical impulses, neurotransmitters, axons, and synapses to deliver fast (milliseconds), short-term, and very specific signals.

Endocrine system

A signaling system that uses hormones released into the bloodstream to produce slower, long-term, and potentially broad effects across multiple organs.

Conscious processes

Voluntary actions that require awareness and intentional control, driven by decision-making in higher brain regions such as the cerebral cortex.

Unconscious processes

Automatic, involuntary processes that occur without awareness or thought, serving homeostatic or protective functions primarily controlled by the spinal cord or lower brain centers like the medulla.

Sensory neurons

Specialized cells that convey messages from environmental receptors detecting light, temperature, or pressure along axons toward the central nervous system.

Cerebral hemispheres

The largest part of the brain, responsible for higher-order functions including decision-making, memory, and initiating voluntary muscle movement via the primary motor cortex.

Reflex arc

The neural pathway followed by nerve impulses during a reflex action, involving sensory neurons, motor neurons, and sometimes interneurons, signaling through the spinal cord rather than the brain.

Cerebellum

The part of the brain that receives sensory input from proprioceptors and motor instructions from the cerebral cortex to coordinate voluntary muscle performance, balance, and spatial orientation.

Melatonin

A hormone secreted by the pineal gland that regulates sleep-wake cycles, whose secretion is signaled by the suprachiasmatic nucleus (SCN) in the hypothalamus as daylight fades.

Epinephrine

A hormone and neurotransmitter (also known as adrenaline) produced by the adrenal medulla during sympathetic stimulation to prepare the body for 'fight or flight' responses.

Hypothalamus

A region of the brain responsible for regulating physiological processes and controlling the endocrine system by sending signals to the pituitary gland.

Pituitary gland

A small gland at the base of the brain divided into anterior and posterior parts that secretes hormones controlling other endocrine glands.

Baroreceptors

Pressure-sensitive nerve endings located in the walls of major arteries (such as the aorta and carotid arteries) that detect blood pressure changes by sensing arterial wall stretch.

Chemoreceptors

Sensory receptors (central and peripheral) that detect changes in oxygen, $CO_2$ concentration, and blood pH to trigger cardiac and respiratory responses in the brainstem.

Peristalsis

Wave-like muscle contractions used voluntarily by the central nervous system for swallowing and egestion, and involuntarily by the enteric nervous system to coordinate the movement of material through the gut.

Phototropism

The growth response of a plant towards or away from light, mediated by light-sensitive pigments in the shoot tip.

Auxin

A phytohormone produced in the shoot tip that promotes cell elongation, accumulating on the shaded side of a shoot to cause uneven growth and bending toward light.

Phytohormones

Signalling chemicals synthesized in various plant tissues that regulate plant growth, development, and environmental responses (e.g., auxins, cytokinins, gibberellins, abscisic acid, and ethylene).

System integration

A necessary process in living systems where coordination is needed for important parts of a system to collectively perform an overall function.

Cells

The basic unit of life.

Tissues

Groups of similar cells performing one function.

Organs

Different tissues working together for a specific function.

Body systems

Groups of organs carrying out broad functions, such as the digestive or nervous system.

Nervous System

A body system using electric impulses and neurotransmitters via nerves (axons and synapses) that provides very fast (milliseconds), short-term, and highly specific signaling.

Endocrine system

A body system using hormones sent through the bloodstream to transmit slower, long-term, and broad messages affecting multiple targets.

The Brain

The central organ of the nervous system responsible for processing sensory information combined from several inputs, learning, memory, and controlling various bodily functions.

Conscious processes

Voluntary actions that require awareness, intention, and decision-making, processed by higher brain regions like the cerebral cortex.

Unconscious processes

Automatic, involuntary actions that occur without thought or awareness, often serving protective or homeostatic functions, controlled by the spinal cord or lower brain centers like the medulla.

Sensory neurons

Specialized cells that convey messages from receptors detecting environmental changes to the central nervous system to assist in responding to stimuli.

Cerebral hemispheres

The largest part of the brain, responsible for higher-order functions such as decision-making, memory, and controlling voluntary muscle movement.

Reflex arc

The pathway followed by nerve impulses during a reflex action—including sensory neurons, motor neurons, and sometimes interneurons—sending signals through the spinal cord rather than the brain.

Cerebellum

The part of the brain responsible for managing balance and spatial orientation and coordinating voluntary muscle performance by receiving sensory input from proprioceptors and motor instructions from the cerebral cortex.

Melatonin

A hormone secreted by the pineal gland in a diurnal pattern to regulate sleep-wake cycles; its production is stimulated when fading daylight is detected by the retina and signaled to the SCN in the hypothalamus.

Epinephrine

A hormone and neurotransmitter (also known as adrenaline) produced by the adrenal glands that prepares the body for fight or flight responses during stress or excitement.

Hypothalamus

A region of the brain responsible for regulating many physiological processes, including the endocrine system, by sending signals to the pituitary gland.

Pituitary gland

A small gland at the base of the brain divided into anterior and posterior parts that secretes hormones controlling other endocrine glands.

Baroreceptors

Pressure-sensitive nerve endings in the walls of major arteries, such as the aorta and carotid arteries, that detect blood pressure changes by sensing the stretch of arterial walls.

Chemoreceptors

Sensory receptors (central and peripheral) that detect changes in blood oxygen, $CO_2$ concentration, and blood pH to signal cardiovascular and respiratory centers in the brainstem.

Peristalsis

Waves of muscular contraction in the digestive system under involuntary control by the enteric nervous system (ENS), though swallowing and egestion of faeces use peristalsis under voluntary central nervous system control.

Phototropism

The growth response of a plant towards or away from light, detected by light-sensitive pigments in the shoot tip.

Auxin

A phytohormone that promotes cell elongation; it accumulates on the shaded side of a shoot to cause uneven cell elongation and bend the shoot toward light.

Phytohormones

Signalling chemicals synthesized in various tissues that regulate plant growth, development, and responses to environmental stimuli, including auxins, cytokinins, gibberellins, abscisic acid, and ethylene.