Human Body Physiology Overview

Organelles containing oxidizers that utilize hydrogen peroxide to break down substances like fatty acids. They self-replicate and can convert alcohol into fuel.

These organelles are responsible for cellular energy production, converting nutrients into ATP. They are found in all cells and are more concentrated where energy is needed.

A network of protein filaments that provides structure and support for the cell. It helps with cell shape, movement, and contraction of muscles.

Strong, rope-like filaments that work with microtubules to provide strength and support in all cells.

Long, hollow tubes that provide a rigid structure for the cell, helping to determine its shape and allowing movement.

The control center of the cell, containing DNA and sending messages for growth, maturation, replication, or death.

The nuclear envelope is actually two separate bilayer membranes. The outer membrane is continuous with the endoplasmic reticulum. It has pores that allow molecules to pass through.

These pores are found on the nuclear envelope and allow molecules to pass in and out of the nucleus.

The majority of cells, excluding fat cells, are composed of 70% to 85% water, which is essential for various cellular processes.

Potassium, magnesium, phosphate, sulfate, bicarbonate, and small amounts of sodium chloride and calcium play crucial roles in maintaining cellular functions.

Proteins, the second most abundant component of cells, constitute 10% to 20% of the cell's composition. They exist in two main forms: structural and functional.

Structural proteins, mainly present as long filaments, are crucial for providing shape and support to the cell and its organelles. Examples include microtubules, cilia, nerve axons, and meiotic spindles.

Functional proteins, often mobile and globular in shape, act primarily as enzymes that catalyze cellular reactions.

Lipids, a diverse group of substances, are grouped together due to their ability to dissolve in organic solutions but not in water. They are crucial for forming cell membranes and other barriers within the cell.

Phospholipids, a type of lipid, are mainly insoluble in water and are essential for building the cell membrane and internal membrane barriers.

Carbohydrates are primarily used for energy and structure within the cell, although most cells don't store large amounts of them. Glucose, a simple sugar, is readily available in the surrounding extracellular fluid.

The ability of a solution to cause a change in cell volume due to the concentration of impermeable solids.

A solution that causes no change in cell volume. The concentration of solutes inside and outside the cell are equal.

A solution with a higher concentration of solutes than the cell. Water moves out of the cell, causing it to shrink.

A solution with a lower concentration of solutes than the cell. Water moves into the cell, causing it to swell.

The rapid movement of water across cell membranes, often correcting osmolarity differences within seconds or minutes. However, it doesn't immediately equilibrate the whole body.

A condition where the sodium concentration in the extracellular fluid is low. It can be caused by either losing sodium or adding excess water.

The primary effect of adding an isotonic saline solution to the extracellular fluid is an increase in the extracellular fluid volume.

When a hypertonic solution is added to the extracellular fluid, it increases extracellular osmolarity, causing water to move out of the cells, resulting in cell shrinkage and an increase in extracellular fluid volume.

The sodium channels close and the potassium channels open, allowing for the rapid loss of potassium ions to the exterior and no flow of sodium ions to the interior. This results in the action potential quickly returning to its baseline.

During the early portion of the action potential, more sodium ions flow into the cell than potassium ions flow out, causing the membrane potential to become positive.

The process where an initial small rise in membrane potential triggers more sodium channels to open, causing a rapid increase in sodium influx, which further depolarizes the membrane, leading to the opening of even more sodium channels. This cycle continues until all voltage-gated sodium channels are activated.

The change in membrane potential required to trigger the positive feedback loop and initiate an action potential.

The electrical signal that travels along the membrane of a nerve or muscle cell. It is caused by the rapid movement of ions across the membrane.

The ability of the action potential to travel in both directions from the point of stimulation.

The period during which the activation gate of the sodium channel will not reopen until the membrane potential returns towards the resting membrane potential

The state where the cell membrane is at rest. The potential difference across the membrane is maintained at a relatively constant value.

The four main forces that govern fluid movement between capillaries and interstitial fluid. These forces are responsible for the balance of fluid in our bodies.

The pressure exerted by blood inside capillaries, pushing fluid outward.

The pressure exerted by fluid in the interstitial space, pushing fluid back into capillaries.

The pressure exerted by proteins in the blood, pulling fluid into the capillaries.

The pressure exerted by proteins in the interstitial fluid, pulling fluid out of the capillaries.

The difference between filtration pressure and reabsorption pressure, determining the net movement of fluid.

A network of vessels that collect excess fluid from the interstitial spaces and return it to the bloodstream.

The process of fluid moving from the interstitial spaces back into the capillaries at the venous end.

Abnormal leakage of fluid from blood vessels into the surrounding tissues, often due to increased pressure within blood vessels or reduced protein levels in the blood.

A condition where the heart cannot effectively pump blood, leading to increased pressure in capillaries and fluid buildup.

Failure of the kidneys to filter and remove excess salt and water from the body. This can lead to fluid buildup in the tissues.

A condition where the liver is damaged, impairing its ability to produce proteins. Reduced protein levels can lead to decreased osmotic pressure and edema.

Spaces between tissues that typically contain a small amount of fluid, allowing for sliding and flexibility. These spaces can fill with excessive fluid during edema.

The process of regulating the balance of acids and bases in the body, which is essential for maintaining proper cell function.

Enzymes, which are proteins that catalyze biochemical reactions, are sensitive to changes in hydrogen ion concentration (pH).