Week Three: Respiratory System Flashcards
What is the primary function of the respiratory system?
Bring oxygen into the body and carbon dioxide out of it
What are the secondary functions of the respiratory system?
Voice production (phonation)
Regulation of body temperature
Regulation of acid base balance (O2/CO2)
Sense of smell
What is external respiration?
Exchange of oxygen and carbon dioxide between the inhaled air and the blood flowing through the pulmonary capillaries
What is internal respiration?
Exchange of oxygen and carbon dioxide between the blood in the systemic capillaries and all the cells and tissues of the body
Structures of the upper respiratory system include…
Nostrils Nasal passages Pharynx Larynx Trachea
What are the nares (nostrils)
External openings of the respiratory tube that lead into the nasal passages
What are nasal passages?
Between the nostrils and the pharynx
What is the nasal septum?
Separates the left and right nasal passage
What are the hard and soft palates?
Separate the nasal passages from the mouth
What are turbinates (nasal conchae)
Divide each nasal passage into three main passageways
Thin, scroll-like bones covered with nasal epithelium
What are nasal passages lined with?
Pseudostratified columnar epithelium
What is mucus in the nose secreted by?
Mucus glands and goblet cells
What are the functions of the nasal passages?
Warm, humidify, and filter inhaled air
What are paranasal sinuses?
Cillated outpouchings of the nasal passages contained within spaces in certain skull bones
(Secrete mucus)
Most animals have two frontal sinuses and two maxillary sinuses
What is the pharynx?
Common passageway for respiratory and digestive system
Why is the soft palate important for the pharynx?
Soft palate divides pharynx into the dorsal nasopharynx (respiratory passageway) and the ventral oropharynx (digestive passageway)
What happens when you swallow?
Breathing stops, opening into larynx is covered, material to be swalled moves to rear of pharynx and breathing resumes
What is the larynx?
Short, irregular tube connecting pharynx with the trachea
Composed of segments of cartilage that connect to each other and surrounding tissues by muscles
What holds the larynx in place?
Hyoid bone
What is the epiglottis?
Leaf shaped and projects forward from the ventral portion of the larynx
(during swallowing it is pulled back to cover the opening of the larynx)
What are arytenoid cartilages?
Attachment is the site of vocal cords
What forms the boundaries of the glottis?
Arytenoid cartilages and vocal cords
What are vocal cords?
Two connective tissue bands attached to the arytenoid cartilages
Stretched across lumen of larynx parallel to each other
Vibrate as air passes over them
What controls the tension of vocal cords?
Muscles attached to the arytenoid cartilages:
Complete relaxtion opens the glottis wide: no sound
Lessening the tension produces lower-pitched sounds
Tightening the tension produced higher-pitched sounds
What is the function of the larynx?
Prevention of foreign material being inhaled
Controls airflow to and from the lungs
Where is the trachea located?
Extends from larynx into thorax
Divides into two main bronchi that enter the lungs
Structures of the lower respiratory tract include…
Bronchi
Bronchioles
Alveolar ducts
Alveoli
Describe the bronchial tree
Each bronchus divides into smaller bronchi, which divide into smaller bronchi, and then tiny bronchioles
Bronchioles subdivide into alveolar ducts
Alveolar ducts end in groups of alveoli which are arranged like bunches of grapes
What are alveolar sacs?
Groups of alveoli
What is bronchodilation?
Bronchial smooth muscle relaxes (aids respiratory effort during intense physical activity)
What is bronchoconstriction?
Bronchial smooth muscle partially contracts
Reduces size of air passage
What is alveoli?
Site of external respiration
Tiny, thin walled sacs of simple squamous epithelium
Surrounded by networks of capillaries
Lined with fluid that contains surfactant
(net surrounding ball)
What is hilus?
Small, well defined area on medial side of lung
Site where air, blood, lymph, and nerves enter and leave the lung
(attaches at bronchi)
Where does deoxygenated blood enter the lungs?
From right ventricle of heart through the pulmonary artery
Where does oxygenated return to the heart?
Left side of heart
What is the mediastinum?
Area between lungs
Contains heart, trachea, esophagus, blood vessels, nerves, lymphatic structures
Divides throacid cavity in two parts
What is the pleura?
Thin membrane that lines thoracic cavity and covers organs and structures in the thorax
The visceral layer of pleura is where?
Covers thoracic organs and structures
Parietal layer of pleura is where?
Lines the cavity
What is the diaphragm?
Thin, dome shaped skeletal muscle sheet
Forms caudal boundary of thorax
Flattens when it contracts, enlarges volume of thorax and aids inspiration
What is inspiration?
Process of drawing air into lungs (inhalation)
Results from enlargement of volume of thoracic cavity by inspiratory muscles
What are the main inspiratory muscles?
Diaphragm and external intercostal muscles
What is expiration?
Process of pushing air out of the lungs (exhalation)
What are the main expiratory muscles?
Internal intercostal muscles and abdominal muscles
What is tidal volume?
Volume of air inspired and expired during one breath
What is minute volume?
Volume of air inspired and expired during one minute of breathing
What is residual volume?
Volume of air remaining in lungs after maximum expiration
Describe alveolar gas exchange
Simple diffusion of gas molecules according to concentration gradient
O2 diffuses from alveolar air into the blood of alveolar capillary
CO2 diffuses from blood into alveolus
What controls respiratory muscle contractions?
Medulla oblongata of the brain stem
This directs timing and strength of contractions
What are individual control centers?
Inspiration, expiration, breath holding
Can be consciously controlled for brief periods
What sets limits on routing resting inspiration and expiration in the lungs?
Stretch receptors
What do chemical receptors in the carotid artery and aorta do?
Monitor blood CO2, pH, and O2
Increased CO2 in blood and _______ blood pH triggers respiratory center to increase rate and depth of respiration
Decreased
Decreased CO2 in blood _________ blood pH, which triggers respiratory center to decrease rate and depth of respiration
Increased
What is hypoxia?
Decrease in blood O2 level
What is severe hypoxia?
neurons of respiratory center can become so depressed that adequate nerve impulses cannot be sent to the respiratory muscles
Can cause breathing to decrease of stop completely
