PLTW Human Body Systems Second Semester Practice Flashcards

Comprehensive vocabulary flashcards covering joint motion, brain anatomy/function, neuron structure, and nervous system signaling based on the semester study guide.

Extensor muscles of the forearm

Muscles located on the posterior side of the forearm that act to straighten or extend the wrist and fingers, increasing the joint angle.

Extension

Movement that increases the angle of a joint.

Flexors

Muscles that act to curl the wrist and fingers, which is the opposite movement of extensors.

Goniometer

A device used to measure the range of motion (ROM) of a joint.

Motor cortex

A region of the brain responsible for initiating and controlling voluntary muscle actions, such as walking or speaking.

Sensory cortex

A region of the brain that receives and interprets sensory input from the body, including touch, temperature, pain, and body position.

Gyri and Sulci

The ridges (gyri) and grooves (sulci) on the brain's surface that dramatically increase surface area for more neurons and processing power.

Villi and Microvilli

Small structures in the small intestine that increase surface area for the absorption of nutrients.

Ulnar nerve

The nerve responsible for stimulating the flexor muscles based on its placement.

Radial nerve

The nerve responsible for stimulating the extensor muscles based on its placement.

Central Nervous System (CNS)

Consists of the brain and spinal cord; it processes information and makes decisions for the body.

Peripheral Nervous System (PNS)

The part of the nervous system that gathers sensory data and carries out motor commands between the body and the CNS.

Frontal lobe

Located anterior to all other lobes; responsible for happiness, speech production, reasoning, and problem-solving.

Parietal lobe

Positioned posterior to the frontal lobe and superior to the temporal lobe; it processes sensory information.

Temporal lobe

Found on the lateral sides of the cerebrum, inferior to the frontal and parietal lobes; responsible for processing sound.

Occipital lobe

The most posterior and somewhat inferior lobe, responsible for visual processing.

Insula

A brain region buried deep within the lateral sulcus, medial to the temporal lobe, responsible for taste.

Developmental milestones

Snapshots of nervous system maturation indicated by how a child plays, acts, communicates, or learns.

Trochlear nerve (CN IV)

The nerve that controls the superior oblique muscle; a lesion results in vertical double vision and difficulty looking down and in.

Olfactory bulbs

Brain structures used for smell; they are much larger in sheep than in humans because sheep rely more on smell for survival.

fMRI (functional magnetic resonance imaging)

A brain scan that shows specific areas activated during certain tasks, often used in research as a lie detector test.

Amygdala

The part of the brain responsible for feeling emotions such as stress.

Hippocampus

The part of the brain responsible for memory.

Cerebellum

A brain structure responsible for coordination and balance; damage leads to clumsiness or motor impairments.

Dendrite

The part of a neuron that receives input from other cells, represented as the branches of a tree.

Axon

The part of a neuron that transmits signals, represented as the roots of a tree.

Soma

The cell body of a neuron, represented as the trunk of a tree.

Sensory neurons

Neurons that carry information into the central nervous system from receptors like the skin, eyes, and ears.

Motor neurons

Neurons that carry signals out from the brain and spinal cord to muscles and glands.

Interneurons

Neurons within the brain and spinal cord that connect sensory and motor pathways, allowing for complex processing and reflexes.

Action potential

A quick electrical signal that travels down a neuron's axon when stimulated, involving the movement of $Na^+$ and $K^+$ ions.

Neurotransmitters

Small messenger molecules that convey chemical signals between neurons at the synapse.

Stimulants

A class of drugs that increases neurotransmitters like dopamine and norepinephrine to speed up brain activity.

Depressants

A class of drugs that enhances GABA to slow down neural firing.

Local anesthetics

Drugs that reversibly bind to $Na^+$ channels, blocking the movement of sodium ions and preventing neurons from firing pain signals.

Reward pathway

A brain circuit that reinforces behaviors like eating by releasing dopamine.

Reflexes

Automatic, fast responses that occur without conscious thought, with signals traveling only through the spinal cord.

Voluntary actions

Intentional movements controlled by the motor cortex of the brain, which are slower than reflexes.

EMG electrodes

Sensors that detect when a muscle becomes electrically active.

Force sensor

A device that records when muscle activation produces actual physical movement.