Human Biology: A Comprehensive Overview of Organ Systems

Posted on Nov 7, 2024 in Biology

Human Biology

Circulatory System

Arteries

Structure: Arteries have thick, slightly elastic walls to withstand high pressure from the heart’s pumping action.

Function: Arteries carry oxygenated, nutrient-rich blood away from the heart. Muscle contractions in artery walls regulate blood flow to organs.

Veins

Structure: Veins have thinner walls and one-way valves to prevent backflow.

Function: Veins return deoxygenated blood carrying cellular waste to the heart. Muscle contractions also control blood volume.

Capillaries

Function: Capillaries connect arteries and veins, delivering oxygen and nutrients to cells while collecting carbon dioxide and waste.

Pulmonary Emphysema

This condition involves the destruction of alveoli walls, reducing the surface area for gas exchange. Smoking is a major cause and increases the risk of respiratory tract cancer.

Breathing

Inspiration: Muscles contract, expanding lung volume and drawing in oxygen-rich air. This process requires energy.

Expiration: Muscles relax, decreasing lung volume and expelling carbon dioxide-rich air. This process is passive.

Respiratory Function: The overall function is to take in oxygen and release carbon dioxide.

Red Blood Cells (RBCs) and White Blood Cells (WBCs)

RBCs travel through the circulatory system, carrying oxygen from the lungs to the body and returning carbon dioxide. Oxygen and carbon dioxide bind to hemoglobin, an iron-containing molecule within RBCs.

Functional Differences: RBCs transport oxygen, while WBCs are part of the immune system.

Structural Differences: RBCs lack a nucleus, while WBCs have one.

Heart Function and Blood Flow

Blood flows through the heart in a specific sequence, regulated by valves. Systolic phase: Ventricles contract, pushing blood to the lungs and body. Diastolic phase: Blood flows from the lungs and body into the atria.

Heart Murmur

A heart murmur occurs when blood flows back between heart chambers, briefly reversing the normal direction. This often resolves naturally but may require intervention in some cases.

Digestive System

The Small Intestine

The small intestine has three levels of adaptation for nutrient absorption:

  1. Folds (Plicae Circulares): The intestine folds upon itself.
  2. Microvilli: Tiny projections on the intestinal wall increase surface area.
  3. Enterocytes: Cells lining the microvilli have further extensions for absorption.

Intestinal Digestion

Intestinal Juices: Produced by the intestinal walls, these contain enzymes like pepsin, lipases, and amylases to break down proteins, fats, and carbohydrates.

Pancreatic Juice: Produced in the pancreas and delivered to the duodenum via the pancreatic duct, this juice contains enzymes to break down proteins, fats, carbohydrates, and nucleic acids.

Bile: Produced by the liver and stored in the gallbladder, bile emulsifies fats, aiding in their digestion and absorption of fatty acids and vitamins A, D, and K.

Food Functions

  1. Energy Function: Carbohydrates and fats provide energy for bodily functions and activities.
  2. Structural Function: Proteins and minerals provide building blocks for new structures.
  3. Regulatory Function: Vitamins and minerals regulate metabolic processes.

Lipids

  1. Energy Reserve: Lipids are the body’s primary energy store.
  2. Structural Component: Lipids form cell membranes and provide cushioning and protection.
  3. Biocatalysts: Lipids facilitate chemical reactions.
  4. Transporters: Lipids aid in the transport of molecules.

Nervous System

Glial Cells

Glial cells support neurons and their functions, though they do not transmit nerve impulses themselves.

Neurotransmitters

Neurotransmitters are molecules released by neurons to transmit signals across synapses to other neurons or cells.

Synapses

Synapses are junctions between neurons where communication occurs.

Central Nervous System (CNS)

The CNS consists of the brain and spinal cord, protected by the skull and vertebrae, respectively. Both are covered by meninges and surrounded by cerebrospinal fluid.

Excretory System

Sweat Glands

. They are the glands that remove the sweat outside, a urine-like substance, therefore it is cellular debris that are produced by cells and transported through the circulation to the glands. The elimination of sweat is a process that helps regulate body temperature, and that when we perform intense exercise tends to increase body temperature, sweating and causes the temperature is stable at 37 º. DISEASES OF THE CIRCULATORY ATHEROSCLEROSIS. It is produced by an accumulation of cholesterol we eat in excess and that is deposited on the walls of blood vessels forming atheroma. The blood vessel diameter decreases and increases blood pressure and can reach off the atheroma or thrombus leading to thrombosis. If this occurs in the head leads to a stroke and if it occurs in the heart results in myocardial infarction. VARICES. This is an increase in diameter of the vein that carries blood to the heart due to the semilunar valves are damaged. This problem is compounded when you are standing a long time, when you perform a moderate exercise during pregnancy and when there are problems of obesity. Cardiac Arrhythmias. The blood normally circulates in the heart because there is a structure called a nodule is the one that controls muscle contraction and relaxation. If the node fails suffers heart arrhythmias and these people tend to tire more, then you need the placement of a pacemaker, a small stack node sends nerve impulses to the heart. The kidneys: two bean-shaped organs located in the back and lower abdomen. The kidneys are made up of about a million nephrons. Each nephron vein blood comes loaded with cellular debris, so that cell debris and part of the water goes to the glomerulus, between now and then to handle Hemler renal tubule and here’s the connecting pipe to reach the renal pelvis . ♥