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Flashcards in Biology Deck (67)
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What are the tenets of cell theory?

1)All living things are composed of cells
2)cells are the basic functional units of life
3)Cells arise only from other cells
4) Cells store information in DNA/nucleic acids


What is a quiescent state for cells?

When cells don't actively divide, G0


What is the stage before G0?

G1, as once the cell enter S to synthesize its DNA it has devoted itself to replicating


What are Sertoli cells?

Sertoli cells are supportive cells in the tubulus


What are leydig cells?

Leydig cells are cells which secrete testosterone


What is the anatomical pathway for sperm development?

Sperm are produced in seminiferous tubules and stored in the epididymus for maturation


Where are sperm produced?

Sperm are produced in the seminiferous tubules


Where are sperm stored for maturation?

Sperm are strored in the epididymis for maturation


What are pluripotent cells?

Pluripotent cells are cell which can become many, but not all, cell types


What are totipotent stem cells?

Totipotent stem cells are cells which can become any cell type


What are differentiated cells?

They are cells which are no longer able to become all cell types


What is the purpose of the ductus venosus in the fetus?

The ductus venosis in the fetus connects the maternal and fetal circulations such as reducing blood flow to the liver


What is the purpose of the foreamen ovale in the fetus?

The foreamen ovale in the fetus moves blood from the right to the left atrium


What is the purpose of the ductus arteriosus in the fetus?

In the fetus, the ductus arteriosus connects the pulmonary artery to the aorta, allowing for blood to be shunted away from the pulmonary artery to the aorta, bypassing the lungs


Why is the ductus arteriosus in the fetus important?

By connecting the pulmonary artery to the aorta, it prevents high blood pressure for the still developing fetus


What do both Schwann and oligodendrocytes make?

Both Schwann and oligodendrocytes make myelin


Where are Schwann cells found in comparison with Oligodendrocytes?

Schwann cells are found in the peripheral nervous system while Oligodendrcytes are found in the central nervous system.


What is the first thing when an action potential is generated?

The neuronal membrane is depolarized by an influx of NA+ into the neuron


What happens to permeability when the neuronal membrane is repolarized

The increased permeability of K+ occurs when the neuronal membrane is repolarized


Does calcium ion permeability have an effect on action potential?

No, the influx of calcium only has a role in releasing neurotransmitter vesicles into the synaptic cleft


When does a stimulus directly influence the change of an axon potential?

This only holds true during the relative refractory period


What do steroid hormones most often bind to?

Steroid hormones often bind to intracellular receptors of target cells


How can steroid hormones diffuse past the plasma membrane of the cell into the cytoplasm?

They are made of cholesterol lipophillic rings


What do peptide hormones bind to?

Peptide hormones bind to its receptor on the surface of target cells (an example is insulin)


What does calcitonin do?

Calcitonin antagonizes Parathyroid hormone (PTH) and causes calcium levels to decrease in the blood)


What does the parathyroid hormone do?

The parathyroid hormone causes calcium blood concentration to increase in response to low blood calcium levels. PTH causes the osteoclasts in bone to break down bone, called resorption to increase calcium levels


During when in the menstrual cycle is progesterone highest?

Progesterone peaks about a week after ovulation, so during the luteal phase


Where is most of water reabsorbed?

It is mainly reabsorbed in the collecting ducts of the nephron and is under the control of the anti-diuretic hormone (ADH)


What does ADH do?

ADH, the anti diuretic hormone, causes the filtrate to become more concentrated by increasing the permeability of the collecting duct (more water is reabsorbed)


What modulates the rate of glomerular filtration?

Glomerular filtration occurs at Bowman's capsule