Respiration

Tidal Volume

The amount of air inhaled or exhaled during a normal breath, typically about 500 milliliters in adults

Inspiratory Reserve Volume

The maximum amount of air that can be inhaled after a normal inspiration, usually around 3000 milliliters in adults.

Expiratory Reserve Volume

The maximum amount of air that can be exhaled after a normal expiration, typically about 1200 milliliters in adults.

Residual Volume

The volume of air remaining in the lungs after a maximal exhalation, approximately 1200 milliliters in adults.

Vital Capacity

The total amount of air that can be exhaled after a maximal inhalation, usually around 4800 milliliters in adults.

Inspiratory Capacity

The maximum amount of air that can be inhaled after a normal expiration, typically about 3600 milliliters in adults.

Functional Residual Capacity

The volume of air remaining in the lungs after a normal expiration, approximately 2400 milliliters in adults.

Total Lung Capacity

The total volume of air in the lungs after maximal inhalation, which includes vital capacity and residual volume, generally around 6000 milliliters in adults.

Conducting Division

The part of the respiratory system that conducts air to the lungs and includes the trachea, bronchi, and bronchioles, without participating in gas exchange.

No gas exchange - transportation

Physiological Dead Space

The volume of the lungs where no gas exchange occurs, including any alveoli that are ventilated but not perfused. It can occur in certain lung diseases.

Nasal Cavity

The hollow space located behind the nose, serving as the entrance for air to the respiratory system. It filters, warms, and humidifies incoming air.

Pharynx

The muscular tube connecting the nasal cavity and mouth to the larynx and esophagus, playing a role in both the respiratory and digestive systems.

Epiglottis

A flap of tissue that covers the trachea during swallowing, preventing food and liquids from entering the airways.

Esophagus

The muscular tube that connects the throat (pharynx) to the stomach, allowing the passage of food and liquids.

Trachea

The windpipe that connects the larynx to the bronchi, facilitating the passage of air to and from the lungs.

Hyaline Cartilage - C-shaped rings that support the trachea and keep it open.

Smooth Muscle - tissue that allows the trachea to expand and contract during breathing. Also connects to esophagus and allows for expansion when consuming food

Ciliated Pseudostratified Columnar Epithelium

A type of epithelium found in the respiratory tract that contains cilia and appears to have multiple layers, aiding in the movement of mucus and trapped particles out of the airways.

Tall and skinny

Bronchial Tree (~23 divisions)

Main (primary) bronchi

Secondary (lobar) bronchi

Tertiary (segmental) bronchi

Main (primary) bronchi

The first large branches of the trachea that divide into the left and right lungs, leading to the secondary bronchi.

Bifurcation of trachea

Carina

Carina

the ridge in the trachea where it divides into the left and right main bronchi, important in respiratory anatomy.

Secondary (lobar) bronchi

the branches of the main bronchi that lead to each lobe of the lung, typically there are three on the right and two on the left.

Tertiary (segmental) bronchi

the branches of the secondary bronchi that further divide into smaller bronchi, supplying specific segments of the lungs.

Branch into primary bronchioles

Continue dividing

End in terminal bronchioles

• end of conducting zone; start of respiratory zone

Cartilage and Smooth muscle in Bronchi

Is smaller fragments than trachea and gradually going to disappear and as the bronchi continue to progress, smooth muscle integrates more.

Lining becomes shorter, lose cilia and more cuboidal to do gas exchange

Bronchi

Supported by cartilage

Ciliated epithelium

Mucociliary “escalator”

Mucociliary “escalator”

The mechanism where cilia in the respiratory tract move mucus upwards, trapping dust and pathogens to clear them from the airways.

Ciliated Epithelium

A type of tissue lining the respiratory tract that features hair-like projections (cilia) that beat in a coordinated manner to move mucus and trapped particles out of the airways.

Bronchioles

Wall has smooth musle

Ciliated epithelium

No mucus glands

Respiratory Division

Respiratory Bronchioles

Alveoli

Respiratory Bronchioles

The small airway passages in the lungs that connect to the alveoli and are involved in gas exchange.

Simple cuboidal epithelium

• Gas exchange, but not very effective (too think

Alveoli

The tiny air sacs in the lungs where gas exchange occurs, consisting of a single layer of epithelial cells to facilitate diffusion of oxygen and carbon dioxide.

Simple squamous epithelium

• Perfect for gas exchange (thinner)

Capillary networks of alveoli

The small blood vessels surrounding alveoli that enable the exchange of oxygen and carbon dioxide between the blood and air.

Alveoli Network : ½ a tennis court

Blood in Alveoli : 1 cup of blood

• Means blood exchange is about 1 cell thick

What is respiration?

Respiration is the biochemical process by which cells convert nutrients into energy, producing carbon dioxide and water as byproducts. It involves both aerobic and anaerobic pathways to meet the energy demands of the organism.

Ventilation

External Respiration

Transport

Internal Respiration

Cellular Respiration

Ventilation

The process of moving air in and out of the lungs, allowing for gas exchange to occur between the atmosphere and the alveoli.

External Respiration

The process of gas exchange between the lungs and the blood, where oxygen is taken in and carbon dioxide is expelled.

Transport

The movement of gases, primarily oxygen and carbon dioxide, through the bloodstream between the lungs and the body's tissues.

Internal Respiration

The process of gas exchange that occurs at the cellular level, where oxygen is delivered to cells and carbon dioxide is removed from them.

Cellular Respiration

The metabolic process by which cells convert glucose and oxygen into energy (ATP), while producing carbon dioxide and water as byproducts.

Lungs and Pleural Cavity

The paired organs in the chest responsible for gas exchange, surrounded by a double-layered membrane that facilitates breathing and protects them.

Two lobes on left

Three on the right

Parietal Pleura

Visceral Pleura

Pleural Cavity

Serous Fluid

Parietal Pleura

The outer layer of the pleura that lines the thoracic cavity and covers the lungs, providing a protective barrier.

Visceral Pleura

The inner layer of the pleura that directly covers the lungs, providing a smooth surface for movement during breathing.

Pleural Cavity

The space between the parietal and visceral pleura that contains serous fluid, allowing smooth movement of the lungs during breathing.

Serous Fluid

A lubricating fluid found in the pleural cavity that reduces friction between the parietal and visceral pleura during respiration.

Mechanism of Breathing

The process by which air moves in and out of the lungs through inhalation and exhalation, involving the diaphragm and intercostal muscles.

Atmospheric Pressure

Intra - Alveolar Pressure

Intrapleural Pressure

Atmospheric Pressure

The pressure exerted by the weight of air in the atmosphere on a given area, typically measured in mmHg or atmospheres.

Intra - Alveolar Pressure

The pressure within the alveoli of the lungs that fluctuates with breathing and is essential for air exchange.

Intrapleural Pressure

The pressure within the pleural cavity surrounding the lungs, which helps maintain lung expansion and prevent collapse during breathing.

Normally P_intrapleural < P_{intra-alveolar}

Pneumothorax

occurs when air enters the pleural cavity, leading to lung collapse.

P_intrapleural > P_{intra-alveolar}

Factors Affecting Ventilation

Surface Tension of Water

Surfactant

Compliance

Surface Tension of Water

The cohesive force that occurs at the surface of water, which affects the ability of the lungs to expand and contract during breathing.

Surfactant

A substance that reduces surface tension in the lungs, helping to maintain alveolar stability and preventing collapse.

Compliance

The ability of the lungs and thoracic cavity to stretch and expand during inhalation.

Lungs at Rest (Pressure)

The pressure within the lungs when no air is being inhaled or exhaled, typically equated to atmospheric pressure. This state reflects the equilibrium between the inward elastic recoil of the lungs and the outward recoil of the chest wall.

Basics of Ventilation (Diaphragm)

The process by which air is moved in and out of the lungs, primarily driven by the contraction and relaxation of the diaphragm and intercostal muscles.

Inspiration

The process where the diaphragm and intercostal muscles contract, leading to a decrease in lung pressure and allowing air to flow into the lungs.

Muscles Involved:

• Diaphragm

• External intercostal muscles

• Pectoralis minor

• Sternocleidomastoid

Expiration

The process where the diaphragm and intercostal muscles relax, leading to an increase in lung pressure and allowing air to flow out of the lungs. This process is primarily passive at rest but can be active during forceful breathing.

Usually passive

Muscles of inspiration relax

Elastic tissues recoil

Internal intercostals, abdominal muscles

Pressure flow of a relax muscle

Air can move easy with wider opening to go through

Pressure flow of a tightened (asthmatic) muscle

Sporadic tightening of smooth muscle during exercise

Rescue inhaler has chemical to relax smooth muscles

Control of Breathing

The physiological process by which the body regulates breathing rate and depth to maintain optimal levels of oxygen and carbon dioxide. This is controlled by the respiratory center in the brainstem, responding to various chemical and physical stimuli.

Skeletal Muscle

Respiratory areas

• Respiratory areas

  • Medullary respiratory center

    • Ventral respiratory group

    • Dorsal respiratory group

  • Pontine respiratory areas

    • won’t deal much with this

    • pons - superior to medulla

Ventral Respiratory Group

A cluster of neurons in the medulla's respiratory center that primarily controls the rhythm of breathing, facilitating expiration and, to a lesser extent, inspiration.

Dorsal Respiratory Group

A collection of neurons in the medulla that primarily regulates inspiration and the depth of breathing, helping to fine-tune respiratory patterns.

Dorsal and Ventral Respiratory Group Communication

The interaction between the dorsal and ventral respiratory groups in the medulla ensures a coordinated regulation of both inspiration and expiration, allowing for smooth respiratory patterns.

Dorsal mainly communicates with ventral

Dorsal goes off of different chemical cues that might change rate and depth of breathing

Chemical Composition of Fluids

refers to the specific types and concentrations of solutes, such as ions and gases, present in bodily fluids, which are crucial for maintaining physiological balance and homeostasis.

Priorities

• Blood CO2

• Blood and Cerebrospinal fluid pH

• Blood O2

  • Least important

  • Have to have very low levels to have major effect

Chemical Control of Respiration

refers to the mechanisms by which chemical signals, such as carbon dioxide, oxygen, and pH levels, regulate the rate and depth of breathing to maintain homeostasis and ensure adequate oxygen supply and carbon dioxide removal in the body.

Breathing shallow

• Retaining CO2

• Influences pH

• Receptors pick this up and increase breathing

Central Chemoreceptors

are specialized neurons located in the brainstem that detect changes in carbon dioxide and pH levels in the cerebrospinal fluid, playing a crucial role in regulating respiratory activity.

Peripheral Chemoreceptors

are sensory receptors located outside the central nervous system, primarily in the carotid and aortic bodies, that monitor blood oxygen, carbon dioxide, and pH levels, contributing to the regulation of ventilation and respiratory drive.

Inflation Reflex

is a protective mechanism that inhibits inspiration when the lungs are overly stretched, preventing overinflation and ensuring appropriate lung volume during breathing.

Stimulus - Stretching of lungs

Effectors Stop inhaling by amount of stretch