Electrolyte Physiology

These interdigitating processes wrap around the glomerular capillaries to create the final barrier of the filtration membrane.

The podocyte pedicels (feet)

Any substance larger than ____ is generally blocked from entering the filtrate under normal physiological conditions.

8nm

_____  is the blood pressure within the glomerulus that drives glomerulus filtration; it must be high enough to overcome the opposing capsular pressure.

Glomerular Hydrostatic Pressure

In a _______ solution, the cell swells and may burst/lyse because the solution has a lower solute concentration.

hypotonic

In a _______ solution, the cell shrivel because the solution has a higher solute concentration.

hypertonic

Vitamin D from the sun is roughly _____ times more potent than a supplement.

10,000

Why might someone need Vitamin D supplements despite the sun's potency?

Genetics or extreme sun sensitivity

What are "Granular Cells" and where are they found?

Smooth muscle cells in the Juxtaglomerular Apparatus (JGA).

________ are salts or molecules that ionize in water and are capable of conducting electricity

Electrolytes

A _____ loses electrons (positive charge, like Na⁺).

Cation

An ______ gains electrons (negative charge, like Cl^-).

Anion

What are the two primary regions of a long bone?

• Diaphysis is the shaft (leverage)

• Epiphyses are the ends (joint strength)

The _______ is an external sheath covering the bone that has an outer fibrous layer and an inner osteogenic layer.

Periosteum

____ marrow produces blood cells (in epiphyses of adults); hematopoietic.

Red

_____ marrow is fatty energy storage (in the shaft); fatty tissue.

Yellow

An _______ is the basic structural unit of compact bone that consists of a central canal (blood vessels/nerves) surrounded by concentric lamellae

Osteon

______ are channels that connecting lacunae and allow osteocytes to communicate and share nutrients via gap junctions.

Canaliculi

Name the types of bone cells.

• Osteogenic cells

• Osteoblasts

• Osteocytes

• Osteoclasts

Unlike other bone cells, ______ develop from hematopoietic stem cells, the same marrow stem cells that create white blood cells.

Osteoclasts

What is the composition of the Organic Matrix?

• Collagen

• Protein-carbohydrate complexes

The ________ provides flexibility; without it, bones are brittle and shatter easily.

Organic Matrix

_________, crystallized calcium phosphate salt, is the primary inorganic component (85%) of the bone that provides hardness and weight-bearing strength

Hydroxyapatite

Appositional growth increases bone _____.

Width (diameter)

Interstitial growth increases bone _____ at the plate.

Length

_______ notes that bone remodels itself to withstand the mechanical stresses, specific loads and physical use, it experiences.

 Wolff's Law of Bone

Why does Osteoporosis affect spongy bone more than compact bone?

It has a higher surface area-to-volume ratio, making it more sensitive to osteoclast activity.

What happens to GFR when you intake excess K⁺?

GFR decreases to provide more time for the tubules to excrete the excess

What is the primary function of Calcitriol?

It mainly increases the absorption of dietary calcium from the small intestine.

When is Calcitonin most active?

During childhood

_____ stimulates osteoblasts and inhibits osteoclasts to lower blood calcium; it has a weak effect in adults.

Calcitonin

What is the effect of PTH on the kidneys?

Calcium reabsorption and Phosphate excretion.

What is the hallmark sign of Hypocalcemia?

Muscle tetany (spasms)

_________ is low calcium that makes sodium channels hyper-excitable, leading to spontaneous nerve firing.

Hypocalcemia

Hypercalcemia can lead to _____ and cardiac arrest.

Muscle weakness/depression

________ is excess calcium that binds to sodium channels, making it harder for nerves to fire.

Hypercalcemia

 How does Aldosterone regulate Sodium?

It creates more Na⁺/K⁺ pumps that Increases Na⁺ reabsorption in the DCT/CD.

What are the primary causes of Hyperkalemia?

Renal failure or acidosis.

How does insulin affect Potassium?

Stimulates the Na⁺/K⁺ pump which drives K⁺ into the cells.

_______ is a potassium-sparing diuretic that blocks sodium channels in the distal tubule, preventing the loss of potassium.

Amiloride

Approximately 85-90% of the body's phosphate is stored as part of the ________.

Osseous tissue (Bones)

What is the function of Trabeculae?

 "Struts" in spongy bone are oriented to resist compression while remaining lightweight.

Patient has "carpopedal spasms" after thyroid surgery, after accidental removal of the parathyroid glands. What is this condition?

Hypocalcemia (Trousseau Sign)

A renal failure patient has peaked T-waves on ECG. What is the associated condition?

Hyperkalemia

A marathon runner drinks only water and becomes confused. The ECF is diluted, causing brain cells to swell. What is condition?

 Dilutional Hyponatremia

A post-menopausal woman breaks her hip after a minor trip. Estrogen loss has led to a critical reduction in bone density. What is the condition?

Osteoporosis