Respiratory System/ Test 2

Nose and Nasal Cavity

Filters, warms, and humidifies incoming air.

Vibrissae (nose hairs) trap larger particles.

Nasal conchae create turbulence, helping air contact the mucous membranes.

The external nose is the visible portion; the nasal cavity is inside.

Paranasal Sinuses

Air-filled spaces in the frontal, maxillary, ethmoid, and sphenoid bones.

Help lighten the skull, produce mucus, and add resonance to the voice.

Inflammation of the nasal mucosa is called rhinitis. Inflammation of the sinuses is sinusitis.

Pharynx

• Muscular passageway shared by the respiratory and digestive systems.

• Nasopharynx: behind the nasal cavity.

• Oropharynx: behind the mouth.

• Laryngopharynx: lower region leading toward the larynx and esophagus.

• Enlarged adenoids may obstruct nasal airflow and contribute to mouth breathing.

Larynx- Voice box

Keeps an open airway.

Produces sound through the vocal folds.

Helps protect the lower airway during swallowing.

The epiglottis is elastic cartilage that helps keep food and liquid out of the airway.

Trachea (windpipe)

Conducts air toward the lungs.

C-shaped cartilage rings help prevent collapse.

Mucus traps particles, and cilia move mucus toward the throat.

Smoking damages this clearance system, contributing to smoker’s cough.

Bronchial Tree

Main bronchi branch into smaller bronchi, then bronchioles.

Terminal bronchioles are the smallest airways of the conducting zone.

Respiratory bronchioles lead into the gas-exchange portions of the lungs.

Main bronchi enter the lungs through the hilum.

Alveoli

Tiny air sacs where oxygen and carbon dioxide are exchanged.

Type I alveolar cells form the thin walls for gas diffusion.

Type II alveolar cells produce surfactant, which reduces surface tension and helps prevent collapse.

Alveolar macrophages engulf particles and microorganisms.

An alveolar duct leads into clusters of alveoli; an alveolar sac is a common chamber opening into multiple alveoli.

Lungs and pleurae

Right lung: three lobes — superior, middle, inferior.

Left lung: two lobes — superior and inferior; it is smaller to accommodate the heart.

Pulmonary circulation carries blood to the lungs for gas exchange.

Bronchial circulation supplies oxygenated blood to lung tissues.

Parietal pleura lines the chest wall; visceral pleura covers the lungs.

Pleural fluid reduces friction during breathing.

Pleurisy

inflammation of the pleura, often causing pain when breathing

Pleural effusion

excess fluid in the pleural cavity

Pneumothorax

air in the pleural cavity that can cause lung collapse; treatment may require a chest tube

Atelectasis

collapse of alveoli or part of a lung

Conducting zone

moves, filters, warms, and humidifies air

Ex: nose, nasal cavity, pharynx, larync, trachea, bronchi, bronchioles

Respiratory zone

participates in gas exchange

Tracheal obstruction

a life-threatening emergency requiring the Heimlich Maneuver

Internal Respiration

Between the blood and tissue

systemic capillaries and tissue

External Respiration

blood and alveoli in the lungs

pulmonary capillaries and alveoli

Forced inspiration

scalenes, sternocleoidomastoid, pectoralis minor

Forced expiration

oblique and transverse abdominal muscles, internal intercostals

Blood that just left tissue

low in O2, high in CO2, low in nutrients

Surfactant

Break up surface tension from water lining the inner alveoli

Disrupting the surface tension stops the alveoli from collapsing and allows inflating during inspiration

Infant Respiratory Distress Syndrome: \Premature infants are born with the inability to make surfactant, resulting in alveolar collapse that does not allow lungs to take in air to obtain oxygen

How does O2 move through the body

Enters body from the atmosphere, reaches alveoli, diffuses to bloodstream, released to systemic circulation, unloaded at tissues

How does CO2 move through the body

Produced as a byproduct of cell activity, picked up by bloodstream from tissues, taken to lungs, diffused to alveoli, expired out

What can cause a reduction in lung compliance

Scar tissue, frequent infections, low surfactant, muscle paralysis

In terms of ventilation-perfusion coupling, arteriolar diameter is dependent on the partial pressure of which gas and bronchiolar diameter is dependent on which gas?

Partial pressure of oxygen impacts arteriolar diameter while partial pressure of carbon dioxide influences bronchiolar diameter.

Arteriolar diameter:

- Decrease in PO2 ⇒ arteriolar constriction

- Increase in PO2 ⇒ arteriolar dilation

Bronchiolar diameter:

- Decrease in PCO2 ⇒ bronchiolar constriction

- Increase in PCO2 ⇒ bronchiolar dilation

Why is ventilation-perfusion coupling important?

Ventilation-perfusion coupling bridges the ability of the body to bring in air and the ability to transport gases in/out of the body. Ventilation allows for oxygen to come in and carbon dioxide to go out. Perfusion allows for oxygen to leave the lung and into the tissues, and carbon dioxide to leave the body. If ventilation is good but perfusion is not, air is getting in/out of the lungs but carbon dioxide is not getting to the lungs to leave, and oxygen is not getting to the tissues. If perfusion is good but ventilation is not, carbon dioxide is getting to the lungs and oxygen is able to get to the tissues but the body is not bringing enough air in/out of the lungs.

What is the Bohr effect

As cells metabolize, they produce carbon dioxide and free hydrogen ions (lowers pH). The presence of these chemical substances weakens the bond between oxygen and hemoglobin, resulting in reduced affinity. This leads to increased unloading of oxygen at those tissues.

Eupnea

normal breathing pattern (12-15 breaths per min)

Hypercapnia

too much CO2 in the body

Hyperventilation

• loss of too much CO2, dizziness

Hypoxia

• tissues are not receiving enough oxygen

• Hypoemic hypoxia- low O2 in blood due to less oxygen making it into the body

• Ischemic hypoxia- blockage of vessels

• Anemic hypoxia- Low RBCs, little or abnormal hemoglobin

Asthma

acute episodes and symptom-free periods.

Sleep apnea

• momentary pause in breathing while sleeping

• structural deformity causing obstruction of the airways

Cystic Fibrosis

A genetic disorder that causes the production of abnormally thick and sticky mucus that obstructs airways and ducts.

Treatment: To loosen or thin out mucus (there is no cure)

Chronic bronchitis

• long term inflamattion of airways

• mucus production, airway obstruction, and fibrosis of tissue

Where does respiration occur?

Alveoli and capillaries at tissues

Emphysema

• destruction of alveolar and lung tissue

• permanent enlargement of the alveoli due to trapped air

• Breathing becomes difficult as trapped air maintains higher intra-alveolar pressure, reducing the ability to inspire.

Functions of Digestive System

Ingest

Digest

Absorb

Eliminate

What is the alimentary canal?

Long muscular tube that includes the exact pathway and structures that the food travels through.

Pathway: Mouth (buccal cavity), pharynx (throat), esophagus, stomach, small intestine, large intestine, rectum, anus.

Small intestine

Duodenum, jejunum, ileum

structures of the large intestine in order of pathway

Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal.

Which glands produce secretions to aid in the breakdown of food and what do they each secrete?

• Salivary glands secrete saliva

• gastric glands in stomach secrete gastric juices

• pancreas secretes digestive juices with enzymes that help break down food

• gallbladder secretes bile

Saliva functions

cleanses and moistens the mouth,

assists bolus formation

and helps taste food

Enteric nervous system

Enteric neurons communicate exclusively with digestive organs/activities

operate independently of CNS. It is known as the second brain

is the 3rd branch of the ANS dedicated to the digestive system

Where does peristalsis occur?

all throughout the entire alimentary canal to propel food forward

Xerostomia

dry mouth

Nutrient rich blood is directed towards which organ and why

Nutrient rich blood is directed towards the liver to process, filter, and package nutrients so that they are fit to enter systemic circulation.

Celiac/Gluten Sensitive Enteropathy

no gluten

GERD

Gastroesophageal Reflux Disease; chronic heartburn

What is the significance of minerals in the body?

Essential for body functions:

● Calcium, phosphorus, magnesium = bone health

● Iron = important for hemoglobin

● Iodine = activation of thyroid hormone

● Sodium + chloride = maintain BP

What maintains blood glucose in postabsorptive? state

Glucagon triggers:

● Glycogenolysis in liver

● Glycogenolysis in skeletal muscle

● For gluconeogenesis (if needed): lipolysis in adipose tissue + liver, protein catabolism

What mechanisms increase core body temperature

• Constriction moves blood to core

● Shivering (skeletal muscle activity)

● Increase BMR ⇒ thermogenesis

● Thyroxine increases BMR

What mechanisms lower core body temperatures

• Dilation moves blood away from core

● Sweating

● Voluntary measures: clothing, stop activity