An overview of the digestive system and its functions

A German pathologist named Rudolph Virchow extended this idea by contending that cells arise only from other cells. What is cell theory? A cell is the basic structural and functional unit of living organisms. When you define cell properties, you define the properties of life.

An overview of the digestive system and its functions

Gas Exchange — A vital life-sustaining process where we inhale oxygen O2 and exhale carbon dioxide CO2 [1, 2]. As each and every cell in the body needs O2 to live, humans cannot go without it for more than a few minutes [3]; so, the respiratory system is active all the time.

High levels of CO2 in the blood decreases the pH level increases the acidity of the blood, so getting rid of it helps maintain the acid-base balance [49]. Speech Production — Inhalation is the first step of speech production, with the next two steps being sound production through the vocal folds around the larynx phonationand forming the words or sounds with the vocal folds, mouth, nose, tongue, and jaw articulation [50].

What Does the Respiratory System Do: Its Parts and Their Functions The respiratory system is made up of multiple small and large organs, bones, and muscles, which all work together to accomplish each task of the system.

Broadly classified into the upper and lower respiratory tracts, here are the functions of the different parts: Upper Respiratory System Function of the Nose The nose, specifically the nostrilsare the primary entry- as well as exit-points into the respiratory tract [4].

After entering through the nostrils, the oxygen-rich air flows through the nasal cavitya hollow space lying just behind the nostrils, where it gets moisturized and purified, freed of dust and other particles.

The cleaning work is performed by the mucous membrane and cilia tiny hair-like structures lining the inner walls of the nasal cavity that traps any impurities and sweeps them out of the body through the nostrils [5, 6].

What are the Primary Functions of the Respiratory System

During exhalation, the nasal cavity collects and retains the moisture from the air that is leaving the body [7]. Function of the Mouth During breathing, the mouth acts as the secondary entrance for air to get into the respiratory tract.

So, in case of a blocked nose, or some other similar problem where the air cannot pass through the nasal cavity, the mouth helps with inhalation and exhalation. However, it lacks the mucous membrane and cilia, and so cannot An overview of the digestive system and its functions the air like the nasal cavity [7, 8].

Trace the Airflow Pathway Through the Respiratory System Function of the Pharynx The small tubular structure located right behind the nasal cavity, the pharynx works by letting the inhaled air pass into the next part of the respiratory tract, the larynx [9].

Function of the Larynx It has a simple, yet important purpose in respiration, to let the inhaled air pass into the tracheaand the exhaled air out toward the pharynx and nasal cavity [10].

There is a thin flap, called epiglottisat the superior end of the larynx that closes it off during swallowing so food cannot enter the airways and choke you [11].

It lets the air travel to and from the lungs, through the other parts of the respiratory tract [13]. There are mucus-secreting goblet cells located in the inner lining of the airways, purifying the air on its way in [51].

There are around 20 cartilage rings surrounding the tracheal pipe, attached to each other with smooth muscles and connective tissues that help the trachea to remain flexible, and maintain its shape during breathing [14, 15].

Function of the Bronchi The part of the respiratory tract entering the lungs, the right primary bronchus is responsible for making the air enter the right lung, while the left primary bronchus lets air pass to and from the left lung [16].

Both the tracheal and bronchial walls contain smooth muscles, a type of involuntary muscle that helps regulate the airflow through the airways [17].

When more air is needed, the cartilage rings and smooth muscles make sure the trachea and bronchi can expand well to accommodate the increased flow of air.

Function of the Bronchioles Once the bronchi enter the lungs, they divide into multiple smaller branches or bronchioles that are responsible for carrying the inhaled air into the alveolithe final part of the respiratory tract [18]. Function of the Pulmonary Alveoli There is a cluster of tiny air-filled sacs at the tip of each bronchiole terminal bronchiole known as alveoli.

This is the part of the respiratory system that carries out the gas exchange process [19]. There is a network of blood capillaries surrounding each alveolus.

Once the air reaches the alveoli, their one cell thick membrane makes it possible for the oxygen in it to move into the blood capillaries [20].

Mainly consisting of phospholipids, pulmonary surfactant is responsible for reducing the surface tension within the alveoli to prevent them, and the lungs in turn, from collapsing when the air rushes out during expiration [21, 22].

Respiratory System Functions Function of the Lungs Both the left and right lungs are responsible for keeping the air flowing in and out of the body, so there is a continuous supply of oxygen to the blood. The right lung is divided into three lobes, while the left lung has two.

What is the Human Circulatory System? We explain an overview of the circulatory system including its functions, how it transports oxygen and other nutrients around the body as well as the differences between systemic and circulatory elements. Autonomic Nervous System - Introduction The organs of our body (viscera), such as the heart, intestines and stomach, are regulated by a branch of the nervous system known as the autonomic nervous system. What are the Primary Functions of the Respiratory System. Being one of the major biological systems, it serves a number of purposes in the human body, with three of its main functions being.

Each of these five lobes has the same function, dealing with the deoxygenated blood coming from all over the body [26]. The thoracic or chest cavity, surrounded by 12 pairs of ribs, the vertebral column, and the breastbone or sternum houses the lungs and heart [27].

An overview of the digestive system and its functions

Pleural Membranes and Pleural Cavity: The lungs are surrounded by the visceral pleura outer lung wall membrane and the costal pleura inner lung wall membranewith the space between these two pleural cavity being filled with a lubricating fluid secreted by the pleural membranes [28].

This fluid keeps the membranes from sticking to each other, thus helping the lungs to maintain their flexibility [29]. Function of the Diaphragm The primary muscle of respiration, the diaphragm is located just beneath the lungs, partially inserted into the lower ribs [30].

Digestive System | Cleveland Clinic

Apart from keeping the chest cavity separated from the abdominal cavity, the dome-shaped sheet muscle plays a vital role during inhalation by contracting and flattening at the base of the chest cavity, pulling the ribcage along with it to create a vacuum for the air to rush into the lungs [31].

Once the gas exchange is done, the diaphragm relaxes, coming back to its original dome shape which puts pressure on the ribcage and the lungs, forcing the carbon dioxide-filled air to gush out through the airways [30].

Function of the Intercostal Muscles The 22 pairs of small muscles located between the ribs [32], the intercostal muscles help monitor the movement of the ribcage during breathing [33]. Oxygen-depleted blood from all over the body is carried by the inferior and superior vena cava to the right atrium, which then flows into the right ventricle to be carried to the lungs through the pulmonary artery [34].

As mentioned earlier, the alveoli, the site where the gas exchange actually occurs, are surrounded by a fine net of capillaries, supplied by the pulmonary artery. So, the blood that reaches the pulmonary capillaries has a high partial pressure of carbon dioxide.

On the other hand, the air that reaches the alveoli from the airways has a high partial pressure of oxygen [7]. So, the process of diffusion begins between the thin alveolar membrane and the capillaries, where both oxygen and carbon dioxide rushes from the high-density area to the low-density area, till the former has the higher partial pressure within the blood [35].The limbic system is composed of structures in the brain that deal with emotions (such as anger, happiness and fear) as well as memories.

This article will address the limbic system, its parts and. The pancreas is an organ located in the abdomen. It plays an essential role in converting the food we eat into fuel for the body's cells.

The pancreas has two main functions: an exocrine function that helps in digestion and an endocrine function that regulates blood sugar. Your digestive system is uniquely designed to turn the food you eat into nutrients, which the body uses for energy, growth and cell repair.

Here's how it works.

An overview of the digestive system and its functions

The mouth is the beginning of the. Learn about the veterinary topic of Overview of Colic in Horses. Find specific details on this topic and related topics from the Merck Vet Manual.

The Mucosa

The George Mateljan Foundation is a not-for-profit foundation with no commercial interests or advertising. Our mission is to help you eat and cook the healthiest way for optimal health. The blood vessels serving the digestive system have two functions. They transport the protein and carbohydrate nutrients absorbed by mucosal cells after food is digested in the lumen.

Lipids are absorbed via lacteals, tiny structures of the lymphatic system.

Digestive System Overview : Anatomy & Physiology