2.0 Human Anatomy and Physiology 1 Exam 3

What are the two main divisions of the Nervous System?

Central Nervous System (CNS) and Peripheral Nervous System (PNS).

What is the role of the Central Nervous System (CNS)?

Processes and integrates information.

What does the Peripheral Nervous System (PNS) consist of?

Nerves and ganglia outside the CNS.

Which part of the nervous system controls voluntary movements?

Somatic Nervous System.

What does the Autonomic Nervous System regulate?

Involuntary processes such as heart rate and digestion.

What is the function of sympathetic nervous system?

Controls the 'fight or flight' response.

What is the function of parasympathetic nervous system?

Controls the 'rest and digest' response.

List the functions of the Nervous System.

Sensory input, integration of information, motor output.

What is the function of astrocytes?

Maintain the blood-brain barrier, regulate ion balance, and provide structural support.

What do Oligodendrocytes and Schwann Cells do?

Form myelin sheaths around axons for faster signal conduction.

What is the role of microglia?

Act as immune cells of the CNS, removing debris and pathogens.

What do ependymal cells do?

Line ventricles and produce cerebrospinal fluid.

What is the structure of a Neuron?

Contains a cell body (soma), dendrites, axon, and axon terminals.

What is the function of dendrites?

Receive incoming signals.

What is the resting membrane potential of a neuron?

Typically around -70 mV.

What maintains the resting membrane potential?

The Na⁺/K⁺ pump and ion channels.

What are graded potentials?

Localized changes in membrane potential that can be depolarizing or hyperpolarizing.

What triggers an action potential?

When the membrane potential reaches a threshold of approximately -55 mV.

List the phases of an action potential.

Depolarization, repolarization, and hyperpolarization.

What happens during depolarization?

Na⁺ channels open and Na⁺ enters the cell.

What occurs during repolarization?

K⁺ channels open and K⁺ exits the cell.

What is characteristic of excitatory synapses?

Increase the likelihood of action potential generation.

What do inhibitory synapses do?

Decrease the likelihood of action potential generation.

What is the role of neurotransmitters?

Mediate communication between neurons at synapses.

What is a diverging circuit in neuronal circuits?

A single neuron activates multiple downstream neurons.

What is the role of the thalamus?

Relay station for sensory and motor signals to and from the cerebral cortex.

What does the hypothalamus regulate?

Homeostasis, including temperature, hunger, and thirst.

Name the three parts of the brainstem.

Midbrain, Pons, and Medulla Oblongata.

What functions does the cerebellum serve?

Coordinates fine motor movements, balance, and posture.

What is the function of cerebrospinal fluid (CSF)?

Cushions and protects the brain and spinal cord.

What is hydrocephalus?

Excess cerebrospinal fluid in the ventricles.

What role do nociceptors play?

They are pain receptors activated by damaging stimuli.

Describe two types of pain.

Fast pain (sharp, localized) and slow pain (dull, diffuse).

What are mechanoreceptors?

Receptors that detect touch and vibration.

What kind of receptors detect temperature changes?

Thermoreceptors.

What is the function of photoreceptors?

Detect light for vision.

What are taste buds responsible for?

Detecting different taste modalities (sweet, salty, sour, bitter, umami).

What structures make up the outer layer of the eye?

Sclera and cornea.

What is the role of the iris?

Controls pupil size.

What are rods and cones in the retina?

Photoreceptors for low light/black-and-white vision (rods) and color vision (cones).

What is the pathway of visual signals?

Retina → Optic nerve → Optic chiasm → Optic tracts → Thalamus (LGN) → Visual cortex.

What do the semicircular canals detect?

Rotational movement for balance.

What is referred pain?

Pain perceived in an area distant from its source.

What is the significance of Wallerian degeneration?

A process following axon injury where the distal part degenerates.

List the layers of the meninges.

Dura mater, Arachnoid mater, Pia mater.

What is the primary function of the medulla oblongata?

Controls vital functions such as heart rate, respiration, and blood pressure.

What are the primary brain vesicles formed during development?

Prosencephalon, Mesencephalon, Rhombencephalon.

What major structures does the forebrain develop into?

Telencephalon (cerebrum) and Diencephalon.

What is the function of satellite cells in the PNS?

Surround neuronal cell bodies in ganglia, providing support and nutrients.

What are the components that contribute to the blood-brain barrier?

Astrocytes and tight junctions between endothelial cells.

What is adaptation in sensory systems?

Reduced sensitivity to a constant stimulus.

What are chemical senses?

Senses related to olfaction (smell) and taste.

What is the role of the olfactory bulb?

Transmits olfactory signals to the brain.

What are the three types of receptors classified by location?

Exteroceptors, Interoceptors, Proprioceptors.

What occurs during hyperpolarization?

Excess K⁺ efflux before returning to resting state.

How do endorphins affect pain modulation?

They inhibit pain transmission.

What is the anatomical structure responsible for hearing?

Cochlea.

What is the structure that controls balance?

Vestibular Apparatus.

How does the ciliary body function?

It focuses the lens of the eye.

What does the cochlea transduce?

Sound vibrations into electrical signals.

What reflex is controlled by a reverberating circuit?

Breathing rhythm.

What do encapsulated endings detect?

Touch and pressure.

How does light lead to signal transmission in the retina?

Light converts 11-cis retinal to all-trans retinal in rhodopsin, causing hyperpolarization.

What are two functions of the choroid?

Provides vascular supply to the eye and absorbs excess light.

What role do Schwann cells play in the PNS?

They guide the regrowth of severed axons.

What does the term 'habituation' refer to?

Decreased perception due to central processing, not receptor-level changes.

What are free nerve endings mainly responsible for?

Detecting pain and temperature.

What is the difference between the primary motor cortex and primary sensory cortex?

Primary motor cortex controls voluntary motor functions; primary sensory cortex processes sensory information.

What is the function of the lateral ventricles?

To produce and circulate cerebrospinal fluid.

How does the iris respond to light?

It adjusts the size of the pupil to control the amount of light entering the eye.

What separates the chambers of the heart and maintains one-way blood flow?

Heart valves.

What is the evolutionary significance of the cerebral cortex in mammals?

It is associated with higher cognitive functioning.

What is the anatomical region responsible for reflex actions?

Spinal cord.

What type of potential is triggered due to a strong stimulus?

Action potential.

What is the importance of the optic chiasm?

It allows the visual field information from both eyes to be processed in the opposite hemisphere of the brain.

Where is the primary auditory cortex located?

In the temporal lobe of the brain.

What is the role of the ciliary body?

Changes the shape of the lens for focusing.

What distinguishes the structure of the cochlea?

It contains hair cells that transduce sound vibrations.

What do pacinian corpuscles detect?

Pressure and vibration.

How do signals from taste buds reach the brain?

Via cranial nerves (VII, IX, X).

Which cranial nerve is primarily responsible for olfaction?

Olfactory nerve (CN I).

What is the main disadvantage of central nervous system regeneration?

Limited regeneration capabilities compared to the PNS.

How does the brain benefit from the blood-brain barrier?

It prevents harmful substances from entering the brain.

What are the functions of the arachnoid mater?

Protects the CNS and contains the cerebrospinal fluid.

What is the pathway for auditory signals?

Sound waves to tympanic membrane to ossicles to cochlear hair cells to auditory nerve.

What type of receptor responds to mechanical stimuli?

Mechanoreceptors.

What is the function of the tympanic membrane?

Transforms sound waves into mechanical vibrations.

What area of the brain is responsible for voluntary movement control?

The motor cortex.

What distinguishes A-delta fibers from C fibers in pain perception?

A-delta fibers carry sharp, localized pain; C fibers carry dull, diffuse pain.

What major brain function is the pons involved in?

Regulating breathing rhythm.

What does the primary sensory cortex receive input from?

Sensory receptors throughout the body.

What layer of the eye contains photoreceptors?

Retina.

What is the role of the vestibular system?

It helps maintain balance and spatial orientation.

Where does cerebrospinal fluid circulate in the brain?

In the ventricles and the subarachnoid space.

What role does the gracile nucleus play?

It processes somatosensory information from the body.

What is the function of the primary visual cortex?

Interprets visual stimuli.

What distinguishes the structures in the inner ear?,

They are involved in both hearing and balance.

What is meant by sensory coding?

The process by which sensory receptors convert stimulus energy into a signal.

What occurs at the axon terminals?

Release of neurotransmitters into the synaptic cleft.

How does the nervous system adapt to continuous stimuli?

Through adaptation and habituation.