exam deck 9 Flashcards
Where are olfactory receptors located?
Within ~5 cm² of olfactory mucosa deep in the nasal cavity.
How do olfactory receptor neurons detect odorants?
Cilia on the neurons bind odorants, triggering a G-protein second messenger system
How does olfactory sensitivity compare to taste?
Olfaction has a broader range of sensitivity and is categorized into seven primary smell qualities.
What are the seven primary smell qualities?
Peppermint, musk, floral, ethereal, pungent, putrid, and camphoraceous.
How do bipolar olfactory cells connect to the brain?
They link to the olfactory bulb via short axons.
Where do olfactory bulbs project their signals?
To ipsilateral and contralateral regions of the olfactory cortex via olfactory tracts.
How do bi-directional projections in olfactory pathways contribute to function?
They allow for smell localization.
What happens to the lens during near vision?
Ciliary muscles contract, causing the lens to round up.
What happens to the lens during distant vision?
Ciliary muscles relax, and suspensory ligaments pull the lens into a flatter shape.
What are cone cells specialized for?
Color vision and high acuity in bright light.
What are rod cells specialized for?
Low-light vision and sensitivity to light intensity.
What is lateral inhibition, and what does it enhance?
A neural mechanism that enhances contrast and sharpens visual signals.
Where do retinal ganglion cells (RGCs) project in mammals?
To the lateral geniculate nucleus.
How is the 3D topographical map in visual pathways formed?
By complementary expression of ligands and receptors in nasal and temporal axons.
What is the most common form of color blindness?
Red-green blindness.
What are scotomas, and what causes them?
Blind spots caused by damage to the fovea or retinal lesions.
What is the role of the optic chiasm in visual processing?
It is a decision point where some axons cross to the opposite hemisphere.
What is the average blood volume in a typical adult male?
~5 liters (7-8% of body weight).
Name the main functions of blood.
Transport (gases, nutrients, waste), thermoregulation, pH maintenance, clotting, and defense.
What are the components of plasma?
Plasma is 95% water and contains proteins like albumin, globulin (α, β, γ), and fibrinogen.
What is colloid oncotic pressure?
The pressure exerted by plasma proteins that draws water into capillaries, opposing hydrostatic pressure.
What is hypoproteinemia, and what does it cause?
Abnormally low plasma protein levels, causing edema due to reduced oncotic pressure.
Describe red blood cells (RBCs).
Biconcave, non-nucleated, flexible cells with a 120-day lifespan, transporting gases via hemoglobin.
What stimulates erythropoietin secretion, and where is it produced?
Hypoxia stimulates erythropoietin secretion, primarily from the kidneys (85%) and liver (15%).
What are the five types of white blood cells (WBCs)?
Neutrophils, Basophils, Eosinophils, Monocytes, and Lymphocytes.
Which WBCs respond to bacterial and viral infections?
Neutrophils respond to bacterial infections; lymphocytes respond to viral infections.
How are white blood cells formed (leukopoiesis)?
Leukopoiesis is controlled by cytokines like Colony Stimulating Factors and interleukins, which adapt to infection types.
What are platelets, and what is their function?
Platelets are cell fragments that mediate clotting by adhering to damaged vessel walls.
What governs platelet formation?
Thrombopoietin regulates platelet formation.
Define haematocrit.
Haematocrit is the percentage of red blood cells in blood, normally 40–50%.
What factors influence blood viscosity?
Haematocrit, temperature (higher temp decreases viscosity), and flow rate (lower flow increases viscosity).
