Introduction to Respiration and Anatomy

The exchange of gases between the atmosphere and the lungs.

The exchange of gases between the lungs and the blood.

The exchange of gases between the blood and the body's tissues.

Exchanges gases (oxygen and carbon dioxide).

Part of the respiratory system where gas exchange occurs.

The interior and anterior space of the nose, bounded by the nasal bones and oral cavity. It's divided by the nasal septum.

Air-filled spaces in the skull bones surrounding the nasal cavity, lined with mucous membranes and vibrates for speech/singing

Bony projections in the nasal cavity that swirl inhaled air.

The tissue in the nose containing sensory receptors for smell and lacks goblet cells.

A muscular tube connecting the internal nares (back of the nose) to the cricoid cartilage, a part of the throat.

A tube with nine rings of cartilage, containing vocal cords, allowing for voice production.

Hyaline Cartilage that forms the front of the Larnyx, commonly called the Adam's Apple.

A flap of elastic cartilage that covers the larynx during swallowing.

Folds in the larynx that vibrate to produce sound when air passes through them.

A tube with cartilage rings that keeps the airway open, also known as the windpipe, lined with cilia.

When blood pH is low, the body tries to compensate by increasing the rate and depth of breathing to remove more carbon dioxide (CO2) and increase pH back to normal.

Hyperventilation leads to lower CO2 levels in the blood, causing a condition called hypocapnia.

A state where CO2 levels in the blood are lower than normal.

A state where tissues in the body are not getting enough oxygen.

This reflex prevents overinflation of the lungs during rigorous exercise. It's triggered by stretching receptors in the bronchi and bronchioles.

These are pressure sensors located in the bronchi and bronchioles that detect stretching of the lungs. They send signals to the DRG to stop breathing.

Emotions like stress or anxiety can influence the respiratory center in the brain through the limbic system.

Exercise increases blood flow to the lungs, known as pulmonary perfusion, due to increased ventilation of the alveoli.

The diaphragm contracts, moving downwards, increasing the volume of the thoracic cavity, leading to inhalation.

Contraction of the intercostal muscles (muscles between the ribs) helps expand the chest cavity, further aiding inhalation.

As the thoracic cavity expands, the pressure inside the lungs decreases, creating a pressure gradient that draws air into the lungs.

The diaphragm's contraction accounts for approximately 75% of the air inhaled during normal breathing.

The external intercostal muscles contract, elevating the ribs and further increasing the chest cavity volume, contributing to the remaining 25% of inhaled air.

The negative pressure within the pleural cavity keeps the pleural membrane adhering to the thoracic cavity wall, ensuring that the lungs expand along with the chest wall.

Exhalation is normally a passive process, occurring due to the relaxation of respiratory muscles and the elastic recoil of the lungs.

As the chest cavity decreases, the elastic tissues of the lungs naturally recoil, creating pressure that pushes air out of the lungs.

Active exhalation, used during intense activities like exercise or playing wind instruments, involves contraction of abdominal and internal intercostal muscles, forcefully expelling air from the lungs.

Surfactant, a substance in the alveoli, reduces surface tension, preventing the collapse of alveoli and ensuring efficient breathing.

Pleural effusion, an accumulation of fluid in the pleural cavity, decreases lung volume, leading to difficulty breathing.

Compliance refers to the ability of the lungs and chest wall to stretch and expand, impacting the effort required for breathing.

Resistance encountered by air as it flows through the respiratory system, impacted by airway diameter, smooth muscle contraction, and airway obstruction.

Factors influencing airway resistance include airway diameter, smooth muscle activity, and obstruction or collapse of airways.

Lung volumes are specific measurements of air inhaled, exhaled, or stored, while lung capacities are the sums of specific lung volumes.

Hemoglobin (Hb) contains 4 protein subunits, each with one heme molecule. Oxygen binds to the iron atom in the heme.

The percentage of hemoglobin molecules bound to oxygen.

Several factors affect Hb's affinity for oxygen, including partial pressure of oxygen (PO2), blood acidity, partial pressure of CO2 (PCO2), temperature, intermediate products of glycolysis, and the type of hemoglobin.

At high partial pressures of oxygen (e.g., in the lungs), Hb becomes almost fully saturated with oxygen.

At low partial pressures of oxygen (e.g., in tissues), Hb releases oxygen to the cells.

Increased acidity (low pH) decreases Hb's affinity for oxygen. This promotes oxygen release to tissues.

High CO2 levels lead to lower blood pH, decreasing Hb's affinity for oxygen.

Higher temperatures decrease Hb's affinity for oxygen. This promotes oxygen release to active tissues.

2,3-bisphosphoglycerate (BPG) produced during glycolysis binds to Hb and decreases its affinity for oxygen.

Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin (Hb-A) due to its different structure and lack of BPG binding.

A small percentage of CO2 dissolves directly in blood plasma.

Some CO2 binds to hemoglobin, forming carbaminohemoglobin.

Most CO2 is transported as bicarbonate (HCO3-) in the blood.

Chloride ions (Cl-) move into red blood cells to balance the charge when bicarbonate (HCO3-) diffuses out, ensuring electrical neutrality.

The respiratory center in the brainstem (medulla oblongata and pons) controls breathing rate and depth.

Central and peripheral chemoreceptors detect changes in blood CO2, H+, and oxygen levels, influencing breathing rate.

A serous membrane that wraps around the lungs, creating a space called the pleural cavity. This membrane helps reduce friction and provides surface tension.

The space between the two pleural membranes surrounding the lungs. It contains pleural fluid which reduces friction and provides surface tension.

The inferior portion of the lung that sits on the diaphragm, a dome-shaped muscle involved in breathing.

The superior portion of the lung, extending just above the collarbone.

A region on the medial (inner) surface of the lung that serves as a gateway for structures like bronchi, blood vessels, nerves, and lymphatics.

A concave indentation on the medial surface of the left lung that accommodates the heart.

Deep grooves that divide the lung into lobes. These lobes have their own bronchi.

A fissure that divides the superior and inferior lobes of the lung.

Larger branches of the bronchi that supply each lobe of the lung.

A section of lung tissue supplied by a segmental bronchus, artery, and vein. It's an independent unit that can be surgically removed if needed.

Smaller compartments within the bronchopulmonary segment, each containing a terminal bronchiole, arteriole, venule, and lymph vessel.

Microscopic branches of the bronchi that lead to alveolar ducts and ultimately to the alveoli, the air sacs where gas exchange occurs.

Tiny air sacs in the lungs where gas exchange takes place. They have a large surface area to facilitate efficient exchange of oxygen and carbon dioxide.

A cluster of alveoli that resembles a bunch of grapes. Each alveolus is a tiny balloon-like structure.

Thin, flattened cells that make up the majority of the alveolar wall. Their thinness allows for efficient gas diffusion.

Cuboidal cells found in the septa between alveoli. They secrete surfactant, a substance that reduces surface tension and prevents the walls of alveoli from collapsing.

The thin barrier between the air in the alveoli and the blood in the capillaries. It consists of the alveolar wall, epithelial basement membrane, capillary basement membrane, and capillary endothelium.

Blood vessels that carry deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation.

Blood vessels that branch from the aorta and deliver oxygenated blood to the muscular tissues of the lungs.

The ability of a passageway, like an airway, to remain open and unobstructed.

The diaphragm contracts and flattens, and the external intercostal muscles pull the ribs up and outward, increasing the volume of the thoracic cavity, which in turn lowers the pressure in the lungs.