SciOly flashcards

Neuron

Specialized cell that transmits electrical signals throughout the body.

Dendrite

Part of a neuron that receives incoming signals from other neurons or sensory receptors.

Axon

Carries electrical impulses away from the cell body toward other cells.

Myelin sheath

Insulates axons and increases conduction speed.

Synapse

Junction where neurons communicate with other cells.

Neurotransmitter

Chemical substance released at axon terminals to transmit signals across a synapse.

Action potential

An all-or-none electrical signal that travels along the axon.

Refractory period

Time during which a neuron cannot generate another action potential.

Glial cells

Support and protect neurons.

Resting membrane potential

The electrical potential difference across the membrane of a resting neuron.

Cerebrum

Part of the brain responsible for cognition, sensation, voluntary movement, and memory.

Frontal lobe

Section of the cerebrum responsible for planning, decision making, and voluntary motor control.

Oligodendrocyte

Glial cell that forms myelin in the central nervous system (CNS).

Astrocyte

Glial cell that maintains the blood-brain barrier and regulates extracellular ions.

Cochlea

Fluid-filled structure in the inner ear that contains hair cells for detecting sound vibrations.

Taste bud

Sensory receptor found on the tongue that detects taste sensations.

Hypersecretion

Condition where too much hormone is produced, causing exaggerated effects.

Hyposecretion

Condition where too little hormone is produced, causing deficiency symptoms.

Cortisol

A steroid hormone that increases blood glucose and stress response.

Insulin

Hormone that lowers blood glucose levels.

Diabetes mellitus

Condition characterized by insufficient or ineffective insulin, leading to high blood glucose.

Epilepsy

Disorder involving abnormal electrical activity in the brain that causes seizures.

Astigmatism

Blurred vision caused by an irregular cornea or lens.

Myopia

Condition of nearsightedness caused by an eye that is too long or a cornea that is too curved.

Hyperthyroidism

Condition where the thyroid produces too much T3 and T4.

Cerebral palsy

A disorder resulting from early brain injury, causing movement and posture problems.

Central Nervous System (CNS)

The division of the nervous system that includes the brain and spinal cord.

Peripheral Nervous System (PNS)

Connecting the CNS to the rest of the body, this division includes all nerves outside the brain and spinal cord.

Cerebellum

Located behind the brainstem, it coordinates voluntary movements, balance, and posture.

Medulla Oblongata

The lowest part of the brainstem, responsible for autonomic functions like heart rate and respiration.

Thalamus

The brain's sensory control center that redirects incoming sensory signals to the proper area of the cerebrum.

Glucagon

A hormone produced by the pancreas that works with insulin to regulate blood glucose by raising levels.

Adrenaline (Epinephrine)

A hormone released under stress that increases heart rate and blood pressure to prepare for action.

Retina

The layer in the back of the eye that contains cells sensitive to light, initiating nerve impulses.

Semicircular Canals

3 tiny, fluid-filled tubes in the inner ear that help the brain maintain balance and orientation.

Schwann Cell

The primary glial cell of the peripheral nervous system, which forms the myelin sheath for local axons.

Hypothalamus

Brain region that maintains homeostasis by regulating temperature, hunger, and the endocrine system.

Sympathetic Nervous System

The division of the autonomic nervous system responsible for the fight-or-flight response.

Parasympathetic Nervous System

The division of the autonomic nervous system that promotes rest-and-digest activities.

Nodes of Ranvier

Periodic gaps in the myelin sheath where the axon is exposed, allowing for faster signal transmission.

Occipital Lobe

The part of the cerebrum primarily responsible for processing visual information.

Temporal Lobe

The part of the cerebrum involved in processing auditory information, memory, and language.

Parietal Lobe

The part of the cerebrum that processes sensory information related to touch, pressure, and body position.

Pituitary Gland

Often called the master gland, it secretes hormones that control many other endocrine glands.

Photoreceptors

Specialized cells in the retina, known as rods and cones, that convert light into electrical signals.

Negative Feedback

A control system where the output of a process inhibits its own production to maintain stability.

Saltatory Conduction

The rapid jumping of an action potential from one node of Ranvier to the next in myelinated axons.

Pons

Part of the brainstem that acts as a bridge between the cerebrum and cerebellum; it also regulates breathing.

Limbic System

A group of brain structures, including the hippocampus and amygdala, involved in emotions, motivation, and memory.

Hippocampus

A structure within the temporal lobe critical for the formation of new long-term memories.

Antidiuretic Hormone (ADH)

Produced by the hypothalamus and released by the posterior pituitary, it stimulates water reabsorption in the kidneys.

Parathyroid Hormone (PTH)

Hormone that increases blood calcium levels by stimulating bone breakdown and reducing calcium excretion.

Steroid Hormones

Lipid-soluble hormones derived from cholesterol that can cross the plasma membrane to bind with intracellular receptors.

Organ of Corti

The sensitive element in the inner ear that contains hair cells; it acts as the primary organ of hearing.

Fovea Centralis

A small pit in the center of the retina that contains a high density of cones and provides the sharpest visual acuity.

Parkinson\u2019s Disease

A progressive nervous system disorder characterized by tremors and motor impairment, caused by a loss of dopamine-producing neurons.

Amygdala

A component of the limbic system primarily involved in processing emotions, especially fear and aggression.

Acetylcholine

A key neurotransmitter used at the neuromuscular junction to trigger muscle contraction and in the parasympathetic nervous system.

Meninges

The 3 protective layers surrounding the brain and spinal cord: the dura mater, arachnoid mater, and pia mater.

Reflex Arc

A neural pathway that mediates a reflex action, consisting of a sensory receptor, sensory neuron, interneuron, motor neuron, and effector.

Melatonin

A hormone secreted by the pineal gland that regulates the circadian rhythm and sleep-wake cycles.

Ossicles

The 3 tiny bones in the middle ear—the malleus, incus, and stapes—that amplify and transmit sound vibrations to the cochlea.

Corpus Callosum

The large band of neural fibers connecting the two cerebral hemispheres and carrying messages between them.

Blood-Brain Barrier (BBB)

A highly selective semipermeable border formed by endothelial cells and astrocytes that protects the brain from circulating toxins and pathogens.

Oxytocin

A hormone produced by the hypothalamus and released by the posterior pituitary that stimulates uterine contractions and milk ejection.

Aldosterone

A steroid hormone from the adrenal cortex that regulates salt and water balance by promoting sodium reabsorption in the kidneys.