Human Anatomy and Physiology Chapter 23

Human Anatomy and Physiology Chapter 23

upper respiratory tract

nose, nasal cavity, pharynx, and larynx

lower respiratory tract

trachea, bronchi, bronchioles, respiratory bronchioles, and alveoli

nose

defense for epithelial cells

mucus, secretory antibody IgA, and lymphoid immune cells

mucus

traps dust, pathogens, and debris

secretory IgA

antibody that helps neutralize pathogens on mucosal surfaces

lymphoid immune cells

provide immune defense against inhaled pathogens

nasal cavity

passage of and conditioning (warming and humidifying) air

nasal epithelium

location of olfactory sensory neurons for sense of smell

larynx

passage of air, restricting food, sound production, and expelling particulates

asthma

an allergic reaction resulting in excess constriction of bronchioles and excess production of mucus

parasympathetic nervous system

Causes bronchiole constriction (narrowing of airways)

sympathetic nervous system

Causes bronchiole dilation (widening of airways)

large surface area

the lungs contain millions of alveoli, creating a very large surface where oxygen and carbon dioxide can be exchanged. More surface area allows more gas molecules to diffuse at the same time.

short diffusion distance

The walls of the alveoli and capillaries are only one cell thick, so gases have a very short distance to travel between air and blood. This allows rapid and efficient gas exchange

type I alveolar epithelial cells

exchange of gases between alveoli and blood

type II alveolar epithelial cells

production of surfactant to prevent alveolar collapse during inspiration

upper respiratory tract infections (URIs)

Viral colds and sinus infections. Affect the nose, nasal cavity, pharynx, and larynx. Usually milder and mainly cause congestion, sore throat, and runny nose

lower respiratory tract infections (LRIs)

Pneumonia (viral or bacterial). Affect the bronchioles and alveoli. More serious and impair gas exchange, often causing cough, fever, and shortness of breath

bronchitis

chronic airway inflammation, often triggered by recurrent infections

emphysema

destruction of alveoli caused mainly by environmental factors such as smoking and air pollution

diaphragm

contracts to expand the thoracic cavity

external intercostal muscles

lift the ribs to help expand the thoracic cavity

thoracic expansion

lung volume increases when it expands. this increase in volume causes pressure to decrease and for lung pressure to be lower than the atmospheric pressure.

high elevation

atmospheric pressure decreases

underwater

pressure increases as depth increases (water adds pressure)

tidal volume

change in thoracic volume with inflation and deflation of lungs during quiet breathing

forced expiratory volume

voluntary increase in expiration of air with deflation of lungs in excess of tidal volume

spirometry

a pulmonary function test that measures the volume and flow of air a person can inhale and exhale

spirometry usefulness

helps diagnose lung diseases (such as asthma, COPD, and restrictive disorders), measures lung capacity and airway obstruction, monitors disease progression and response to treatment, and assesses lung function before surgery

respiratory center

medulla of brainstem

respiratory rhythm

changes in blood pressure or blood C02 levels

pressure gradient

the difference in pressure between the atmosphere and the lungs that drives air movement

airflow

The movement of air into and out of the lungs in response to a pressure gradient.

compliance

the ability of the lungs to stretch and expand when filled with air.

elasticity

the ability of the lungs to recoil and return to their original size after stretching.

alveolar to blood interface (lungs)

O₂ diffuses from alveoli into the blood. CO₂ diffuses from blood into the alveoli

blood to tissue interface (body tissues)

O₂ diffuses from blood into tissues. CO₂ diffuses from tissues into the blood

hemoglobin & oxygen transport in lungs

hemoglobin binds O₂ as it diffuses from alveoli into blood

tissues

hemoglobin releases O₂, which diffuses from blood into tissues

hemoglobin and oxygen transport for lungs

oxygen concentration is high in the alveoli, so O₂ diffuses into red blood cells and binds to hemoglobin, forming oxyhemoglobin

Exercise & hemoglobin

lowers PO₂ and pH and raises temperature in tissues, all of which enhance oxygen unloading from hemoglobin

means of carbon dioxide transport

free CO2, hemoglobin bound CO2 and HCO3 (bicarbonate)

most CO2 transport in blood

as bicarbonate (HCO₃⁻)

least CO2 transport in blood

dissolved CO₂ in plasma

enzyme CO2 transport in blood

carbonic anhydrase