Neurophysiology Lecture Notes

Flashcards based on a comprehensive overview of neurophysiology, covering brain structure, function, sensory systems, and associated reflexes and pathways.

What structure in the diencephalon is responsible for processing sensory and motor information?

Thalamus

What hormone does the hypothalamus secrete that controls the anterior pituitary gland?

TRH, CRH, GnRH, PIF, GHRH

What is the primary function of the medulla in the brainstem?

Controls breathing, blood pressure, swallowing, coughing, and vomiting.

What are the three major parts of the brainstem?

Medulla, Pons, Midbrain.

What part of the brain is primarily responsible for coordination of movement?

Cerebellum.

What is ataxia?

Lack of coordination of movement due to cerebellar dysfunction.

Which part of the cerebral cortex sends signals to muscles?

Primary Motor Cortex.

What are the four lobes of the cerebral hemispheres?

Frontal, Temporal, Parietal, Occipital.

What is the name of the structure that is the main relay center for sensory information?

Thalamus.

What are the two parts of the pituitary gland that the hypothalamus communicates with?

Anterior and Posterior Pituitary.

What neurotransmitter is most common in excitation?

Excitation is more common than inhibition.

Which type of glial cells form the myelin sheath in the central nervous system?

Oligodendrocyte.

What are microglial cells responsible for?

Scavenging pathogens and dead cells.

How many pairs of spinal nerves are there?

31 pairs.

What are the two types of sensory pathways in the spinal cord?

Ascending and descending pathways.

What does decussation mean in the context of neurophysiology?

Crossing of nerve fibers from one side of the body to the other.

Describe the main difference between A, B, and C nerve fibers.

A is largest and fastest (myelinated), C is smallest and slowest (unmyelinated).

What is the role of mechanoreceptors in the somatosensory system?

Convert mechanical stimuli into electrical impulses.

What are the four components of the sensory system?

Receptors, sensory pathways, centers (thalamus & sensory cortex), and sensory neurons.

What does the concept of lateral inhibition refer to?

Activation of one area leads to hyperpolarization of surrounding areas, aiding in stimulus localization.

What is the sensory homunculus?

A representation showing which part of the body corresponds to areas of the sensory cortex.

What is the order of sensory neurons?

1st order (dorsal root or spinal ganglion), 2nd order (spinal cord/brainstem), 3rd order (thalamus), 4th order (cerebral cortex).

What are rod cells responsible for in the visual system?

Night vision and seeing in low light.

How does the pupil regulate light entering the eye?

By constricting or dilating.

What is the main focusing mechanism of the eye?

Cornea.

What does the ciliary body do?

Its muscles change the shape of the lens to focus on objects.

What is the function of the auditory nerve (CN VIII)?

Transmits auditory information from the cochlea to the brain.

What are the components of the vestibular system?

Three semicircular canals and the otoliths.

What is the pathway for olfactory transduction?

Odorant molecules bind to receptors, activating G proteins, leading to depolarization of olfactory cilia.

What type of sensory receptor responds to painful stimuli?

Nociceptors.

Which cranial nerve is responsible for taste from the anterior 2/3 of the tongue?

Facial nerve (CN VII).

What type of reflex is the knee-jerk reflex?

Single synapse reflex.

What is the function of gamma motor neurons in muscles?

Regulate sensitivity of intrafusal fibers in muscle spindles.

What part of the brain is involved in coordinating voluntary movement?

Cerebellum.

What is the role of the basal ganglia in movement?

Smooth and coordinate voluntary movements.

What condition is characterized by degeneration of dopamine-producing neurons and leads to tremors?

Parkinson's disease.

What type of adaptation occurs in sensory receptors that stop responding to a constant stimulus?

Phasic adaptation.

What are the two types of receptors involved in pain sensation?

Thermal nociceptors and polymodal nociceptors.

What is the main function of taste buds on the tongue?

Sense different tastes: bitter, sour, sweet, salty, and umami.

What structure in the eye contains the highest concentration of cone cells?

Fovea.

What is phototransduction?

The process by which light stimuli are converted to electrical signals in photoreceptors.

What happens during hyperpolarization of photoreceptors?

Decreased release of glutamate onto bipolar cells, leading to their response alterations.

What structure crosses at the optic chiasm?

Nasal retina fibers.

What can central vision loss indicate after head injury?

Injury above the lateral geniculate body.

What is referred pain and give an example?

Pain felt in a different area than its source, like arm pain during a heart attack.

What is the significance of astrocytes in the nervous system?

Provide structural support and maintain extracellular environment.

How does the auditory system transduce sound waves into nerve impulses?

Sound waves cause vibrations in the organ of Corti, leading to hair cell activation and auditory nerve signaling.

What kind of reflex is the Golgi tendon reflex?

Two synapse reflex that regulates muscle tension.

What type of receptors are responsible for detecting temperature changes?

Thermoreceptors.

Which neurotransmitter is primarily used by inhibitory neurons in the CNS?

GABA.

What happens during depolarization of hair cells in the cochlea?

Increased release of glutamate resulting in action potentials in cochlear nerves.

What sensory system is activated by mechanical stimuli?

Somatosensory system.

Which fiber type is largest and fastest?

Type A fibers.

What is the primary role of the hypothalamus in the endocrine system?

Regulates hormones released by the pituitary gland.

What do rods in the retina primarily detect?

Low light conditions and peripheral vision.

Which cranial nerves are involved in the sensation of taste?

CN VII, IX, and X.

What do the otoliths in the vestibular system detect?

Linear acceleration and deceleration.

Define somatosensory system.

A system that processes sensory information from the skin and body.

How do mechanoreceptors contribute to sensory perception?

They convert mechanical stimuli into electrical signals.

What does the term 'decussate' refer to in neuroanatomy?

The crossing of nerve fibers to the opposite side of the body.

What type of sensory adaptation occurs when receptors stop firing as long as a stimulus remains?

Tonic adaptation.

What type of nerve fibers carry pain signals?

A delta and C fibers.

What does the spinal cord's dorsal column pathway primarily transmit?

Discriminative touch, pressure, vibration, and proprioception.

What part of the central nervous system is responsible for reflex actions?

Spinal cord.

What is the primary function of the thalamus?

Relay sensory information to the cerebral cortex.

What is a common result of chronic exposure to extreme temperatures on temperature receptors?

They can become inactive.

Which part of the brain helps with balance and coordination of movement?

Cerebellum.

What does the term 'homonymous hemianopia' refer to?

Loss of the same visual field in both eyes.

What are the characteristics of C fibers in terms of conduction speed and myelination?

Slowest and unmyelinated.

What does the term 'ipsilateral' mean in neuroanatomy?

Nerve fibers that run on the same side of the body.

What is the primary role of the amygdala in the limbic system?

Processing emotions.

In the context of sensory receptors, what is a larger receptive field indicative of?

Less precise localization of stimulus.

What condition follows damage to the corpus callosum, affecting communication between hemispheres?

Crossed sensory deficits.

What physiological effects result from the activation of larger diameter myelinated fibers?

Faster conduction velocities.

What muscles control the size of the pupil?

Sphincter and dilator pupillae.

What sensory processes are largely associated with the temporal lobe?

Auditory processing.

What do Golgi tendon organs primarily monitor?

Muscle tension.

What part of the eye is directly involved in the process of accommodation?

Lens.

What do the semicircular canals detect?

Rotational movement.