29 Questions
What is the main function of the lens in the eye?
To refract light and focus it onto the retina
What happens to the image formed on the retina?
The image is formed upside-down on the retina
What is the main reason humans and most mammals cannot see infrared light?
Humans lack the necessary receptors to detect infrared light
What is the main purpose of the lens in the eye?
To focus light onto the retina
What is the composition of the lens in the eye?
The lens is composed of ≅1000 layers of cells that lose their nucleus and organelles during development
What is the main symptom of Syringomyelia?
Weakness in hands
Which condition is associated with bilateral loss of pain and temperature sensation?
Syringomyelia
What is the characteristic symptom of Phantom Pain?
Sensation from amputated organs
How does Herpes zoster reach the spinal ganglia?
Through retrograde transport
Which area of the body does Phantom Feeling (phantom pain) typically originate from?
Sensory cortex
What is a common consequence of Syringomyelia in terms of sensory perception?
Loss of pain sensation
What type of receptors are Hair Follicle Receptors?
Phasic
What constitutes a 'sensory unit'?
One sensory axon and its peripheral branches
What determines the intensity of a stimulus?
Both the frequency of impulse transmission and the number of receptors involved simultaneously
According to the Law of Specific Energies, what does not change as the intensity of a stimulus increases?
The type of sensation (modality)
Which of the following can affect senses through central excitation or central inhibition states of the nervous system?
Both opiates and Calcitonin Gene-Related Peptides (CGRP)
Which part of the body has the highest two-point discrimination ability?
Fingertips or lips
What type of receptors are responsible for proprioception, fine touch, and fine pressure?
Muscle spindles, Golgi tendon organs, and Ruffini endings
Which law states that all sensory fibers enter the spinal cord via dorsal roots, and all motor fibers leave the spinal cord via ventral roots?
Bell-Magendie law
Which structure is the first neuron in the dorsal column-medial lemniscus system?
Spinal ganglion (dorsal root ganglion)
Which symptom is associated with lesions in the dorsal column-medial lemniscal system?
Ataxia (drunken-like walking, swinging during eyes closed)
Which structure is the third neuron in the dorsal column-medial lemniscus system?
Ventral posterolateral nucleus of the thalamus
What type of neurotransmitter do all sensory fibers release?
Glutamate
What is the role of HCO3− in saliva?
Reducing the taste intensity of acid
Which enzyme catalyzes the formation of H2CO3 in intracellular fluid?
Carbonic anhydrase
What is the primary active process involved in transporting H+ and K+ against their electrochemical gradients?
H+-K+ ATPase
Which drug is used to inhibit the H+-K+ ATPase in gastric parietal cells?
Omeprazole
What is responsible for the 'alkaline tide' observed in gastric venous blood after a meal?
HCO3− absorption
How is Cl− transported into the lumen of the stomach?
Simple diffusion
Learn about hair follicle receptors and sensory units, and how they respond to different stimuli. Understand the concept of receptive fields and how the intensity of a stimulus is perceived by the nervous system.
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