Science Olympiad Anatomy and Physiology Vocabulary

Central Nervous System (CNS)

Composed of the brain and spinal cord; integrates sensory information and coordinates responses

Cerebrum

Largest brain region responsible for cognition

Frontal Lobe

Controls voluntary movement

Parietal Lobe

Processes somatosensory information such as touch

Temporal Lobe

Involved in hearing

Occipital Lobe

Primary center for vision

Cerebellum

Coordinates balance

Brainstem

Regulates vital functions including breathing

Spinal Cord

Transmits signals between brain and body and mediates reflexes

Dorsal Root

Carries sensory information into the spinal cord

Ventral Root

Carries motor commands out of the spinal cord

EEG Alpha Waves

8–13 Hz waves seen during relaxed wakefulness

EEG Beta Waves

High-frequency waves seen during alert mental activity

EEG Theta Waves

4–7 Hz waves common in light sleep

EEG Delta Waves

Low-frequency waves seen in deep sleep

Neuron

Excitable cell that transmits electrical and chemical signals

Dendrites

Receive incoming signals from other neurons

Axon

Conducts action potentials away from the cell body

Myelin Sheath

Insulating layer that increases conduction velocity

Resting Membrane Potential

Approximately –70 mV maintained by ion gradients and Na⁺/K⁺ pump

Action Potential

Rapid depolarization and repolarization caused by voltage-gated Na⁺ and K⁺ channels

Saltatory Conduction

Action potential “jumps” between nodes of Ranvier in myelinated axons

Astrocytes

Glial cells that support neurons and maintain blood-brain barrier

Oligodendrocytes

Form myelin in the CNS

Schwann Cells

Form myelin in the PNS

Microglia

Immune defense cells of the CNS

Synapse

Junction between neurons where neurotransmitters transmit signals

Acetylcholine

Neurotransmitter involved in muscle contraction and memory

Dopamine

Neurotransmitter involved in reward and motor control

Peripheral Nervous System (PNS)

Nerves and ganglia outside the CNS

Sensory Neurons

Carry information from receptors to CNS

Motor Neurons

Carry commands from CNS to muscles and glands

Somatic Nervous System

Controls voluntary skeletal muscle movement

Autonomic Nervous System

Controls involuntary functions of organs

Sympathetic Nervous System

“Fight or flight” system increasing heart rate and energy use

Parasympathetic Nervous System

“Rest and digest” system conserving energy

Reflex Arc

Rapid automatic response involving sensory neuron

Epilepsy

Disorder characterized by recurrent seizures from abnormal electrical activity

Alzheimer’s Disease

Neurodegenerative disorder causing memory loss and cognitive decline

Multiple Sclerosis

Autoimmune destruction of CNS myelin

Parkinson’s Disease

Degeneration of dopamine neurons causing tremors and rigidity

Cerebral Palsy

Motor impairment due to early brain damage

Stroke

Loss of brain function due to interrupted blood flow

Amyotrophic Lateral Sclerosis (ALS)

Degeneration of motor neurons leading to muscle weakness

Alcohol

Depressant that slows CNS activity and impairs coordination

Caffeine

Stimulant that blocks adenosine receptors and increases alertness

Nicotine

Stimulates acetylcholine receptors and increases dopamine release

Marijuana (THC)

Binds cannabinoid receptors altering mood

Cornea

Transparent outer layer that refracts incoming light

Lens

Flexible structure that focuses light onto the retina

Iris

Colored muscle controlling pupil size

Pupil

Opening that regulates amount of light entering eye

Retina

Light-sensitive layer containing rods and cones

Optic Nerve

Transmits visual information to the brain

Rods

Photoreceptors for low-light and peripheral vision

Cones

Photoreceptors for color and sharp central vision

Outer Ear

Includes pinna and ear canal; collects sound waves

Middle Ear

Contains eardrum and ossicles that amplify vibrations

Inner Ear

Contains cochlea and semicircular canals

Cochlea

Converts sound vibrations into neural signals

Hair Cells

Sensory receptors that detect sound frequency and amplitude

Semicircular Canals

Detect rotational movement for balance

Vestibular System

Maintains balance and spatial orientation

Olfactory Epithelium

Contains receptors for smell in nasal cavity

Olfactory Bulb

Brain structure that processes smell signals

Taste Buds

Contain taste receptor cells for detecting chemicals

Papillae

Structures on tongue housing taste buds

Gustatory Nerves

Transmit taste information to brain

Myopia

Nearsightedness caused by elongated eyeball

Hyperopia

Farsightedness caused by shortened eyeball

Presbyopia

Age-related loss of lens elasticity

Nyctalopia

Night blindness due to rod dysfunction

Astigmatism

Irregular cornea curvature causing blurred vision

Conjunctivitis

Inflammation of the conjunctiva

Color Blindness

Inability to distinguish certain colors due to cone defects

Otitis Externa

Infection of outer ear canal

Otitis Media

Infection of middle ear

Conductive Deafness

Hearing loss from sound transmission problems

Sensorineural Deafness

Hearing loss from inner ear or nerve damage

Anosmia

Loss of sense of smell

Dysgeusia

Distorted sense of taste

Steroid Hormones

Lipid-soluble hormones derived from cholesterol that act on intracellular receptors

Peptide Hormones

Water-soluble hormones that bind membrane receptors

Amine Hormones

Derived from amino acids; may be water- or lipid-soluble

Nuclear Receptors

Intracellular receptors that alter gene transcription

Second Messenger System

Cytoplasmic signaling pathway activated by membrane receptors

Hypersecretion

Excess hormone production

Hyposecretion

Insufficient hormone production

Hypothalamus

Controls pituitary via releasing and inhibiting hormones

Pituitary Gland

“Master gland” regulating other endocrine glands

Pineal Gland

Secretes melatonin regulating circadian rhythms

Thyroid Gland

Produces T3 and T4 to regulate metabolism

Parathyroid Glands

Secrete PTH to regulate blood calcium

Thymus

Produces thymosin for T-cell maturation

Adrenal Glands

Produce cortisol

Pancreas

Produces insulin and glucagon for blood glucose regulation

Gonads

Ovaries and testes producing sex hormones

Diabetes Mellitus

Disorder of insulin deficiency or resistance causing high blood glucose