Zenuwstelsel en Zintuigen - Phys : The nervous system: Sensory systems

16 important questions on Zenuwstelsel en Zintuigen - Phys : The nervous system: Sensory systems

What kind of viceral receptors does the body have?

chemoreceptors (detect oxygen etc in bloodvessels), baroreceptors (bloodpressure), mechanoreceptors (stretch in gastrointestinal tract).

What are labeled lines?

Specific neural pathways that transmit information pertaining to a particular modality.

What are sensory units?

single afferent neurons and all the reecptors associated with them. 
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart

What chambers/segments are found in the eye and where? (name the fluid found there)

The anterior segment is in front of the lens and ciliary body and is devided into an anterior chamber between the conea and iris and a posterior chamber between the lens and the iris. The anterior segment contains a cleas fluid called aqueous humor (supplies nutrients). The posterior segment is found behind the lens and ciliary body and is also called the vitreous chamber containing the jelly like substance vitreous humor.

 How does the eyelens work?

It consists of two smoothe muscle layers, the inner circular muscle (constrictor muscle) and the radial muscle (dialator muscle). When the circular muscles contract, the diameter of the pupil decreases thus causing pupillary constriction. The radial muscles are arranged as spikes on a wheen and by contracting, increase the pupil diameter (pupillary dialation).

Under which nervous system is the iris controlled by? And accomadation?

The iris by autonomic nervous system. Parasympathetic neurons innervate the cirucal muscles; activity causes the circular muscles to contract, producting pupillary constriction. Sympathetic neurons innervate the radial muscles; activity in these causes the radial muscles to contract producting dialation.

Accomatation is under control of the parasympathetic nervous system, which triggers contraction of the ciliary muscle for near vision. In the absence of parasympathetic activity the ciliary muscle relaxes.

What is the macula lutea (in the retina)?

A depression in the center of the retina, allowing light to reach the fovea without having to pass through bloodvessels and the ganglion and bipolar cells.

What is macular degeneration and what kinds are there?

Impaired vision as people age sometimes caused by diabetes. The two forms are wet and dry. Dry -> the photoreceptors in the macula lutea degenerate resulting in blurry vision. Wet-> New blood vessels develop (angiogenisis) within and behind the retina, these vessesls are weak and burst easily.

What is phototransduction? And how does it work?

The conversion of lightwaves into neural signals, carried out by the rods and cones. The rods and cones consist of an inner and outer segment. The inner segment contains the cell nucleus and organells and ends in the synaptic terminal and is where a chemical messenger is stored in synaptic vesicles. The outer segment membranous disks whose molecules absorb light (photopigment, protein typ opsin determins the wavelength absorbable). Each of the four types (one in rods, three in cones) of photoreceptors contain a different pigment. OMG to complicated, see 278 in pysiology.

 What is scoptic vision, photopic vision and mesopic vision?

Scoptic -> black and white monochromatic, photopic -> colous vision, mesopic vision -> when rods and cones are activated together.

What does the iexternal ear inculde?

The pinna and the external auditory meatus (ear canal) gather sondwaves and direct them to the tympanic membrane (eardrum).

What is found in the middle ear and what is it's function?

To amplify sound waves. Three ossicles -> malleus, incus and tapes extend from the tympanic membrane toe a thin membrane the ovel window. The round window also connects the middle and inner ear. The eustachian tube connects the middle ear with the pharynx (throat) to maintain the right pressure.

What structures are found in the inner ear?

The cochlea contains the receptor cells for hearing. The vestibular apparatus contains the semicircular canals. The nerves that contains the afferents for both hearing and equillibrium, crainial nerve VIII, is the vestibulocochlear nerve.

How does the cochlea work?

When vibrations occur at the oval window, waves are generated in the perilympf of the scala vestibuli and travel through the scala tympani, where they cause motion of the round window (allows the vibrations to occur in the fluid).

How is the organ of Corti organized?

It is located in the cochlea on top of the basilar membrane. It contains haircells (stereocilia, tips embeded in the tectorial membrane), supporting cells and overlying membran called the tectorial membrane. There are three rows of haircells and one row of inner haircells. The haircells are at a electrical potential of -70mV.

How is sound coded in the cochlea?

Receptor potentials are produced by the bending of stereocilia. Louder sounds cause the sterocilia to bend farther in each direction, causing larger changes in the number of open potassium channels, resulting in larger receptor potentials and larger variations in transmitter release. The frequency is based on the location of the hair cells on the basilar membrane which is harder to bring in to vibrations near the end of the coil.

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo