Anatomy & Physiology Ch. 7 Vocab p2.

Depolarization

The process during which an inward rush of sodium ions occurs, leading to a change in the polarity of the neuron's membrane, making the inside of the neuron more positively charged compared to the outside.

Graded Potential

A change in the electrical charge of a neuron's membrane where the inside becomes more positive relative to the outside, typically in response to a stimulus.

Action Potential

A rapid electrical signal, or nerve impulse, that travels along the axon of a neuron after reaching a certain threshold of depolarization.

Nerve Impulse

Another term for action potential, reflecting the conduction of an electrical signal along a nerve fiber.

Repolarization

The phase in which the outflow of positive ions, primarily potassium, restores the electrical conditions at the neuron's membrane back to its polarized or resting state.

Reflexes

Automatic, rapid, predictable responses to specific stimuli that are involuntary and do not require conscious thought.

Reflex arcs

Neural pathways that mediate reflex actions, which consist of sensory neurons, interneurons, and motor neurons, involving both the central nervous system (CNS) and peripheral nervous system (PNS).

Somatic Reflexes

Reflex actions that cause contraction of skeletal muscles, yet they occur involuntarily, such as the knee-jerk reflex.

Autonomic Reflexes

Reflex actions that regulate the activity of smooth muscles, heart function, and glandular secretions, and are essential for homeostasis.

Cerebral Hemispheres

The two symmetrical halves of the cerebrum, responsible for higher functions such as thought, memory, and sensory processing.

Cerebrum

The largest and most superior part of the brain, responsible for voluntary activities, sensory perception, cognition, and memory.

Gyri

Elevated ridges or folds on the brain's surface that increase the surface area for more neurons.

Sulci

Shallow grooves on the brain's surface that separate gyri from one another.

Fissures

Deep grooves that separate major regions of the brain, such as the longitudinal fissure which divides the cerebral hemispheres.

Lobes

Distinct regions of the brain named for the cranial bones that lie over them; these include the frontal, parietal, temporal, and occipital lobes.

Cerebral Cortex

The outer layer of the cerebrum where complex functions occur, including speech, memory, logical and emotional responses, consciousness, sensation interpretation, and voluntary motor control.

Primary Somatic Sensory Area

A specific region located in the postcentral gyrus of the parietal lobe, responsible for processing general sensory information from the body, like touch, pressure, temperature, and pain.

Parietal Lobe

Region at the top and back of the head, mainly involved in processing sensory information related to touch, temperature, pain, and spatial orientation.

Central Sulcus

A prominent groove that serves as a major dividing line between the frontal lobe and the parietal lobe.

Sensory Homunculus

A visual representation that maps the areas of the body to specific regions of the cerebral cortex responsible for processing sensory information.

Occipital Lobe

The brain’s posterior region responsible for processing visual information, including aspects of vision such as color, motion, and depth.

Temporal Lobe

Region of the brain primarily responsible for processing auditory information and encoding memories, as well as aspects of language.

Primary Motor Area

An area in the frontal lobe that directly controls voluntary movements throughout the body, enabling the movement of arms, hands, legs, face, and eyes.

Pyramidal Tract (Corticospinal Tract)

A pathway in the central nervous system that enables voluntary movement control of the body and face, originating from neurons in the motor cortex.

Motor Homunculus

A representation of the parts of the body in the brain's motor cortex, illustrating the motor control associated with different body parts.

Broca’s Area

A critical region in the frontal lobe responsible for speech production and articulation, influencing language processing and fluency.

Anterior Association Area

Region of the cerebral cortex involved in complex cognitive functions such as planning, decision-making, working memory, and intricate problem-solving.

Posterior Association Area

Area of the brain responsible for perception, language processing, and spatial awareness, integrating information from multiple sensory modalities.

Speech Area

Another term generally referring to regions such as Broca’s area, involved in the production and articulation of speech.

Cerebral White Matter

Tissue composed primarily of myelinated axons that facilitate communication between different brain regions.

Corpus Callosum

A significant bundle of nerve fibers that connects the left and right cerebral hemispheres, allowing for interhemispheric communication.

Basal Nuclei

A group of nuclei in the brain that play a crucial role in the regulation of voluntary movement, learning, and emotional behavior.

Diencephalon (interbrain)

A vital brain region located between the cerebrum and brainstem that relays sensory information and regulates autonomic functions. Key components include the thalamus, hypothalamus, and pineal gland—essential for maintaining homeostasis.

Thalamus

The part of the diencephalon that serves as a sensory relay center for the brain, processing and directing sensory data.

Hypothalamus

A crucial brain region that governs various autonomic functions such as regulating hunger, thirst, sleep, body temperature, and stress responses, linking the nervous system to the endocrine system.

Limbic system

A complex set of brain structures involved in emotional regulation, memory formation, and motivational processes.

Pituitary gland

A small gland located at the base of the brain that secretes hormones regulating various physiological processes and endocrine functions.

Pineal gland

A small gland in the brain that produces melatonin, which regulates sleep-wake cycles and seasonal rhythms.

Choroid plexus

A network of blood vessels and tissue in the brain's ventricles that produces cerebrospinal fluid.

Brain stem

The region of the brain that connects to the spinal cord, responsible for controlling vital functions such as heart rate, breathing, and blood pressure.

Midbrain

The upper part of the brainstem, involved in functions such as vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.

Pons

The part of the brainstem situated below the midbrain and above the medulla oblongata, playing a key role in sleep regulation and relaying information between the cerebellum and cerebrum.

Medulla Oblongata

The lowest part of the brainstem that connects to the spinal cord, responsible for regulating essential involuntary functions such as heart rate, blood pressure, and respiration.

Cerebellum

A region at the back of the brain responsible for coordinating voluntary movements, balance, and motor control.

Meninges

Three protective membranes—the dura mater, arachnoid mater, and pia mater—that envelop the brain and spinal cord, providing protection and support.

Dura Mater

The outermost, tough layer of the meninges that provides a protective covering for the brain and spinal cord.

Arachnoid mater

The middle layer of the meninges, characterized by a web-like structure, which provides a cushioning effect for the brain.

Pia mater

The innermost layer of the meninges that closely adheres to the surface of the brain and spinal cord, containing blood vessels that supply nutrients.

Meningitis

An inflammation of the protective membranes (meninges) surrounding the brain and spinal cord, usually due to infection.

Cerebrospinal fluid (CSF)

A clear fluid produced in the choroid plexus of the brain that circulates around and through the brain and spinal cord, providing cushioning, nutrients, and waste removal.

Ventricles

Fluid-filled spaces within the brain that contain cerebrospinal fluid, helping to cushion and protect the brain.

Hydrocephalus

A condition characterized by an accumulation of cerebrospinal fluid within the ventricles of the brain, leading to increased intracranial pressure.

Blood-brain barrier

A selective permeability barrier that protects the brain from harmful substances in the bloodstream, while allowing essential nutrients to pass.

Concussion

A mild traumatic brain injury resulting from a blow to the head, leading to temporary disruption in brain function.

Contusion

A bruise on the brain resulting from direct impact, often leading to localized bleeding and tissue damage.

Intracranial hemorrhage

Bleeding within the cranial cavity, which can arise from trauma or other conditions, potentially increasing pressure on brain tissue.

Cerebral edema

Swelling of brain tissue due to the accumulation of excess fluid, which may cause increased intracranial pressure.

Cerebrovascular accidents (CVA)

Commonly referred to as strokes, these are disruptions in the blood supply to the brain, leading to tissue damage and loss of function.

Hemiplegia

Paralysis of one side of the body, often resulting from brain injury or stroke affecting motor control.

Aphasia

A language disorder that affects a person's ability to communicate, typically due to brain damage, impairing speech, writing, or comprehension.

Transient ischemic attack (TIA)

A temporary period of symptoms similar to those of a stroke; it occurs when blood flow to a part of the brain is briefly interrupted.

Spinal Cord

The cylindrical bundle of nerve fibers and associated tissue that runs down the back, transmitting signals between the brain and the rest of the body.

Cauda Equina

A bundle of spinal nerves located at the lower end of the spinal cord, resembling a horse’s tail, responsible for innervating the pelvic organs and lower limbs.

Dorsal/Posterior horns

Regions of gray matter in the spinal cord that receive sensory information from the body.

Ventral/Anterior horns

Regions of gray matter in the spinal cord that contain motor neurons which send signals to muscles.

Dorsal root

The sensory root of a spinal nerve that carries sensory information from the body to the spinal cord.

Dorsal root ganglion

A cluster of sensory neuron cell bodies located in the dorsal root of a spinal nerve.

Ventral root

The motor root of a spinal nerve that transmits motor commands from the spinal cord to the muscles.

Spinal nerves

Mixed nerves that emerge from the spinal cord, containing both sensory and motor fibers.

Peripheral Nervous System (PNS)

The part of the nervous system outside of the brain and spinal cord, including sensory and motor neurons that connect the CNS to the rest of the body.

Endoneurium

The delicate connective tissue that surrounds individual nerve fibers within a nerve.

Perineurium

The protective sheath that surrounds a group of nerve fibers, forming a fascicle.

Fascicles

Bundles of nerve fibers within a nerve, each surrounded by a perineurium.

Epineurium

The outermost layer of connective tissue that encloses multiple fascicles, forming the entire nerve.

Sensory (afferent) nerves

Nerves that carry sensory information from the body to the central nervous system (CNS).

Motor (efferent) nerves

Nerves that transmit motor commands from the central nervous system (CNS) to muscles and glands.

Mixed nerves

Nerves that contain both sensory and motor fibers, capable of transmitting both sensory information and motor commands.

Cranial nerves

Twelve pairs of nerves that arise directly from the brain, responsible for various sensory and motor functions of the head and neck.

Spinal Nerves

Thirty-one pairs of nerves that emerge from the spinal cord, each compressing both sensory and motor fibers.

Autonomic nervous system (ANS)

The part of the peripheral nervous system that controls involuntary bodily functions, such as heart rate and digestion.

Sympathetic division

The part of the autonomic nervous system responsible for the 'fight or flight' response, preparing the body for action.

Parasympathetic division

The part of the autonomic nervous system responsible for 'rest and digest' functions, promoting relaxation and recovery.

Cerebral palsy

A group of neurological disorders that permanently affect body movement and muscle coordination, resulting from damage to the developing brain.

Anencephaly

A severe congenital condition characterized by the absence of a major portion of the brain, skull, and scalp.

Spina bifida

A birth defect where the neural tube does not close completely, resulting in incomplete formation of the spinal cord and its protective covering.

Orthostatic hypotension

A form of low blood pressure that occurs when standing up from sitting or lying down, leading to dizziness or fainting.

Arteriosclerosis

A disease characterized by the thickening and hardening of arterial walls, leading to reduced blood flow and potential cardiovascular complications.

Senility

The progressive deterioration of mental faculties associated with aging, often manifesting as memory loss, confusion, and cognitive decline.