Chapter 15 Respiratory System Flashcards
Respiration
Process of bringing oxygen to all body cells and carrying carbon dioxide in opposite direction
2 steps
*External respiration
*Internal respiration
External and Internal Respiration
External respiration – exchange of O2 and CO2 between inhaled air and pulmonary capillaries
* Occurs in the lungs
Internal respiration – exchange of O2 and CO2 between blood in systemic capillaries and all cells and tissues of the body
* Occurs in the body tissues
Respiratory System Functions
Primary function: bring O2 into the body and CO2 out of it
* Respiratory system works together with the cardiovascular system
Secondary functions
*Phonation (voice production)
* Regulation of body temperature
* Regulation of acid-base balance
*Sense of smell
Voice Production
= Phonation
Begins in larynx = voice box
Vocal cords = vocal folds
*Stretch across lumen of larynx
*Vibrate as air passes over them
*Produce basic sound of animal’s voice
Body Temperature Regulation (respiratory)
Involves many body systems
Utilizes superficial blood vessels lining nasal passages
*Inhaled air is warmed to prevent hypothermia
*Panting increases evaporation of fluids to cool circulating blood
Acid-Base Balance respiration
Important homeostatic mechanism of the animal body
Necessary for normal chemical reactions in cells
Respiratory system influences amount of CO2 in blood by the rate of breathing
* The more CO2, the lower the blood pH
* Normal pH of blood = 7.4 (range 7.35-7.45)
The Sense of Smell
= Olfactory Sense
Receptors for sense of smell located in sensory epithelium
* Located high in nasal passages
The Respiratory Tract
Lungs and system of tubes that connect lungs to the outside world
* Upper respiratory tract
—All structures outside the lungs
* Lower respiratory tract
—All structures within the lungs
Fix this card
Trace a molecule of O2 from the air to bloodstream of animal
* Upper Respiratory Tract
* Lower Respiratory Tract
Upper Respiratory Tract
Outside of lungs
Nostrils
Nasal Cavity
*Passages
Pharynx
Epiglottis
Larynx
Trachea
*Bifurcation
Nose and Nasal Passages
External openings of respiratory tube = nostrils = nares
Nasal passages lie between nares and pharynx
Midline is called the nasal septum
Nasal Passages
Lining:
*Pseudostratified columnar epithelium, cilia, mucus, blood vessels
Main function is to condition inhaled air
* Warming
* Humidifying
* Filtering
Nasal Passage Functions
Inhaled air warmed by blood flowing through blood vessels just beneath nasal epithelium
Inhaled air humidified by mucus and other fluids on epithelial surface
Inhaled air filtered as it passes through winding passages produced by turbinates
*Particles trapped in mucous layer
* Cilia move mucus and trapped foreign material upward to pharynx, mouth
Nasal Turbinates
(Nasal Conchae)
Divide each nasal passage into 3 main passageways
Thin, scroll-like bones covered with nasal epithelium
Dorsal and ventral
Another Important Nasal Passages Function
Olfactory sense
Sensory neurons leading to olfactory nerve (cranial nerve I)
Pharynx = Throat
Common passageway for respiratory and digestive systems
Divided at rostral end by soft palate:
* Nasopharynx (respiratory)
* Oropharynx (digestive)
Opens at caudal end into:
* Esophagus (digestive)
* Larynx (respiratory)
Larynx
( Voice Box)
Connects pharynx with the trachea
Supported by hyoid bone
Made mainly of cartilage segments:
* Epiglottis (1)
* Artenoid cartilages (2)
* Thyroid cartilage (1)
* Cricoid cartilage (1)
Larynx
short, irregular tube connecting pharynx with the trachea
Epiglottis
single, leaf shaped; projects forward from the ventral portion of the larynx
* During swallowing, the epiglottis is pulled back to cover the opening of the larynx
* Most rostral of the cartilages
Larynx Functions
Voice Production
* Vocal cords – two connective tissue bands attached to the arytenoid cartilages
* Together form boundaries of the glottis
* Stretched across lumen of larynx parallel to each other
* Vocal cords vibrate as air passes over them
Vocal cords – like a guitar
* Muscles attached to cartilages adjust tension in cords
* Complete relaxation opens the glottis wide; no sound
* Lessening the tension produces lower-pitched sounds
* Tightening the tension produces higher-pitched sounds
Swallowing
Breathing stops, opening into larynx (glottis) is covered by epiglottis, material to be swallowed moves to rear of pharynx, esophagus opens
After swallowing, larynx is reopened and breathing resumes
Trachea
= Windpipe
Short, wide tube
* Fibrous tissue and smooth muscle held open by cartilage rings
–C-shaped rings spaced along length of trachea prevent collapse during inhalation
–Ciliated lining
–Mucous layer
Extends from larynx into thorax where it divides
*Bifurcation of the trachea
Structures of the Lower Respiratory Tract –
The Bronchial Tree
Bronchi
Bronchioles
(bronchial tree)
Alveolar ducts
Alveoli
Autonomic nervous system controls diameter of tubes by adjusting muscle fibers in their walls
*Bronchodilation
*Bronchoconstriction
The Alveoli
Tiny, thin-walled sacs surrounded by capillaries
Sacs lined with a thin layer of fluid that contains a surfactant
External respiration takes place in alveoli
* Oxygen and carbon dioxide exchanged between blood and air