Skip to main content

INTRODUCTION TO RESPIRATORY SYSTEM

When the respiratory system is mentioned, people generally think of breathing, but breathing is only one of the activities of the respiratory system. The body cells need a continuous supply of oxygen for the metabolic processes that are necessary to maintain life. The respiratory system works with the circulatory system to provide this oxygen and to remove the waste products of metabolism. It also helps to regulate pH of the blood.


Respiration is the sequence of events that results in the exchange of oxygen and carbon dioxide between the atmosphere and the body cells. Every 3 to 5 seconds, nerve impulses stimulate the breathing process, or ventilation, which moves air through a series of passages into and out of the lungs. After this, there is an exchange of gases between the lungs and the blood. This is called external respiration. The blood transports the gases to and from the tissue cells. The exchange of gases between the blood and tissue cells is internal respiration. Finally, the cells utilize the oxygen for their specific activities: this is called cellular metabolism, or cellular respiration. Together, these activities constitute respiration.


Mechanics of Ventilation

Ventilation, or breathing, is the movement of air through the conducting passages between the atmosphere and the lungs. The air moves through the passages because of pressure gradients that are produced by contraction of the diaphragm and thoracic muscles.


Pulmonary ventilation

Pulmonary ventilation is commonly referred to as breathing. It is the process of air flowing into the lungs during inspiration (inhalation) and out of the lungs during expiration (exhalation). Air flows because of pressure differences between the atmosphere and the gases inside the lungs.


Air, like other gases, flows from a region with higher pressure to a region with lower pressure. Muscular breathing movements and recoil of elastic tissues create the changes in pressure that result in ventilation. Pulmonary ventilation involves three different pressures:


Atmospheric pressure

Intraalveolar (intrapulmonary) pressure

Intrapleural pressure

Atmospheric pressure is the pressure of the air outside the body. Intraalveolar pressure is the pressure inside the alveoli of the lungs. Intrapleural pressure is the pressure within the pleural cavity. These three pressures are responsible for pulmonary ventilation.


Inspiration

Inspiration (inhalation) is the process of taking air into the lungs. It is the active phase of ventilation because it is the result of muscle contraction. During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. This decreases the intraalveolar pressure so that air flows into the lungs. Inspiration draws air into the lungs.


Expiration

Expiration (exhalation) is the process of letting air out of the lungs during the breathing cycle. During expiration, the relaxation of the diaphragm and elastic recoil of tissue decreases the thoracic volume and increases the intraalveolar pressure. Expiration pushes air out of the lungs.


Respiratory Volumes and Capacities

Under normal conditions, the average adult takes 12 to 15 breaths a minute. A breath is one complete respiratory cycle that consists of one inspiration and one expiration.


An instrument called a spirometer is used to measure the volume of air that moves into and out of the lungs, and the process of taking the measurements is called spirometry. Respiratory (pulmonary) volumes are an important aspect of pulmonary function testing because they can provide information about the physical condition of the lungs.


Respiratory capacity (pulmonary capacity) is the sum of two or more volumes.

Factors such as age, sex, body build, and physical conditioning have an influence on lung volumes and capacities. Lungs usually reach their maximum in capacity in early adulthood and decline with age after that.


Conducting Passages

The respiratory conducting passages are divided into the upper respiratory tract and the lower respiratory tract. The upper respiratory tract includes the nose, pharynx, and larynx. The lower respiratory tract consists of the trachea, bronchial tree, and lungs. These tracts open to the outside and are lined with mucous membranes. In some regions, the membrane has hairs that help filter the air. Other regions may have cilia to propel mucus.


NB: compliment this write up with the class explanation and note.

MR. SANNI HAMMED OLAYINKA

Cc. Training.seer

Comments

Post a Comment

Popular posts from this blog

NERVOUS SYSTEM (INTRODUCTION)

The Nervous System The nervous system is the major controlling, regulatory, and communicating system in the body. It is the center of all mental activity including thought, learning, and memory. Together with the endocrine system, the nervous system is responsible for regulating and maintaining homeostasis. Through its receptors, the nervous system keeps us in touch with our environment, both external and internal. Like other systems in the body, the nervous system is composed of organs, principally the brain, spinal cord, nerves, and ganglia. These, in turn, consist of various tissues, including nerve, blood, and connective tissue. Together these carry out the complex activities of the nervous system. The various activities of the nervous system can be grouped together as three general, overlapping functions: 1. Sensory 2. Integrative 3. Motor Millions of sensory receptors detect changes, called stimuli, which occur inside and outside the body. They monitor such things as temperature,...
Post a Comment
Read more

EXCRETORY SYSTEM

 Excretory System The excretory system is the body system responsible for removing waste products and maintaining a healthy internal environment in the body. Meaning of Excretion Excretion is the process by which the body removes metabolic wastes and harmful substances produced during body activities. Examples of wastes removed: 1. Urea 2. Excess water 3. Salts 4. Carbon dioxide Organs of the Excretory System Main Organs • Kidneys • Skin • Lungs • Liver Functions of the Excretory System The excretory system performs the following functions: • Removes waste products from the body. • Maintains water balance in the body. • Regulates body salts and minerals. • Helps maintain normal body temperature. • Prevents accumulation of harmful substances. • Maintains healthy blood composition. • Helps maintain homeostasis (stable internal environment). Functions of the Excretory Organs 1. Kidney The kidneys are bean-shaped organs located at the back of the abdomen. Functions of the Kidney • Filt...
Post a Comment
Read more

Digestive system

INTRODUCTION TO THE DIGESTIVE SYSTEM The digestive system includes the digestive tract and its accessory organs, which process food into molecules that can be absorbed and utilized by the cells of the body. Food is broken down, bit by bit, until the molecules are small enough to be absorbed and the waste products are eliminated. The digestive tract, also called the alimentary canal or gastrointestinal (GI) tract, consists of a long continuous tube that extends from the mouth to the anus. It includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The tongue and teeth are accessory structures located in the mouth. The salivary glands, liver, gallbladder, and pancreas are major accessory organs that have a role in digestion. These organs secrete fluids into the digestive tract. Food undergoes three types of processes in the body: Digestion Absorption Elimination Digestion and absorption occur in the digestive tract. After the nutrients are absorbed,...
Post a Comment
Read more