Final exam chapter 15 respiratory system

Gas exchange

Supplies oxygen (O2) to the body and removes carbon dioxide, a waste product of cellular respiration

Voice production

The larynx (voice box) houses vocal cords that vibrate to produce sound when air flows through

Regulation of blood Ph

By adjusting breathing rate and CO2 levels, the respiratory system helps maintain the body’s acid-base balance

Olfaction

Airborne molecules stimulate sensory receptors in the nasal cavity, contributing to the sense of smell

Protection

Mucus traps microbes and debris; cilia help move them out of the respiratory tract; coughing expels irritants

Pathway of breathing

Nasal or oral cavity → pharynx → larynx →trachea → bronchi → bronchioles → alveoli

What does the nasal cavity do

Filters, moistens, and warms air

What does the pharynx do

shared passage or food and air

What does larynx do

Routes air to the trachea and food to the esophagus; also involved in sound and production

What does the trachea do

held open by C=shaped cartilage rings

What does the bronchi do

branch into each lung and divide into smaller bronchioles

Alveoli

are tiny, balloon-like air sacs located at the ends of bronchioles and surrounded by a dense network of pulmonary capillaries, brinhing air and blood into close contact

What is the function of alveoli

This is the primary site of gas exchange in the lungs. Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled

What is the structure of alveoli

Thin walls and large surface area and make gas exchange highly efficient

External reparation

The exchange of gases between the alveoli of the lungs and the pulmonary capillaries. Oxygen moves from air sacs into blood; carbon dioxide moves from blood into alveolar air

Internal respiration

The exchange of gas between systemic capillaries and body tissues. Oxygen diffuses into tissues; carbon dioxide diffuses into the blood

O2 concentration is higher in the alveoli and blood than in body tissues

So O2 diffuses into tissues

CO2 concentration is higher in tissues than in blood

So, CO2 diffuses into the blood, then into alveoli to be exhaled

Oxygen (02) transport

98% of 02 binds to hemoglobin in red blood cells, forming oxyhemoglobin. 2% dissolves directly into plasma

Carbon dioxide (CO2) transport

70% is transported as bicarbonate ions (HCO3-) in plasma, formed via the reaction; CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻

20% binds to hemoglobin as carbaminohemoglobin and 10% dissolves directly in plasma

The bicarbonate buffering system helps regulate blood pH:

When CO2 increases, more carbonic acid forms, releasing H+ ions and lowering pH (more acidic)

When CO2 decreases, H+ ions are removed, raising pH (more basic)

Control of respiration

The medulla oblongata in the brainstem controls the basic rhythm of breathing by sending impulses to the diaphragm and intercostal muscles, every 4-5 seconds. Chemoreceptors in the medulla, aortic bodies, and carotid bodies monitor CO2,H+, and O2 levels

Aortic & Carotid bodies location

Near the arch of the aorta (aortic bodies) and at the bifurcation of the carotid arteries in the neck (carotid bodies)

Aortic & Carotid bodies function

Detect changes in blood oxygen concentration. When oxygen levels fall, they signal the respiratory center to increase ventilation

What is the function of the pharynx

Serves as a common passage for both food (to the esophagus) and air (to the larynx)

What is the function of the larynx

Also known as the “voice box”, it routes air to the lungs and food to the esophagus and contains vocal cords for sound production

What is the function of the epiglottis

A flap of tissue that covers the trachea during swallowing, preventing food from entering the airway

What is the function of bronchioles

The smallest conducting airways; they control airway resistance and direct air to the alveoli for gas exchange