ALS 2304 VT Animal Anatomy Final Exam : Respiratory System

nostrils; external openings to the respiratory tract

the space inside the internal nose, divided into two halves by the median nasal septum

communicates with pharynx

• air filled cavities located in frontal, sphenoid, ethnoid, and maxillary bones
• 

• 1. lighten the skull
• 2. moisten air- the lungs hate dryness
• 3. produce mucous
•      a. Rhinitis- inflammation of mucous membrane in nose
•      b. Sinusitis- inflammation of paranasal sinuses.

• 1. external nares
• 2. nasal cavity
• 3. internal nares
• 4. Paranasal sinuses

• connects nasal cavity and mouth to larnyx and esophagus.
• commonly called the throat is directs food and air into the digestive and respiratory systems

• 1. nasopharynx
• 2. oropharynx
• 3. laryngopharynx
• 

• "voice box"
• located between laryngopharynx and trachea

• 1. patent airway
• 2. route air and food to proper channels
• 3. voice production

blocks larynx during swallowing

"windpipe" is a cylindrical tube extending from the larynx to the division into right and left primary bronchi above the base of the heart.

• Primary Bronchi
•    -->Secondary bronchi
•      -->Tertiary bronchi
•        --> Bronchioles
•          --> Terminal bronchioles
•            --> Respiratory bronchioles
•              --> alveoli duct

• 1. Alveoli; single layer of squamous epithelial cells (type I cells) on basal lamina
• 2. Capillary wall
• 3. Type II cells which secrete surfactant
• 4. Alveoli: elastic fibers, alveolar pores & contain alveolar macrophages (dust cells)

• 1. pulmonary ventilation: mechanical movement of air into and out of the lungs
• 2. External respiration is the exchange of gases between the lungs and the pulmonary capillaries
• 3. Internal respiration is the exchange of gases between systemic capillaries and tissue.

• active process using inspiratory muscles (diaphragm and intercostal muscles)
• as the diaphragm contracts, it increases the size of the thoracic cavity which causes the volume of the lungs to expand and decreases the pressure inside the lungs

recruits extra muscles to inhale more. uses scalenes, sternocleidomastoid, and pectoralis minor

• passive: depends on elasticity of lungs, elastic recoil of lungs and chest cavity
• due to pressure gradients in the opposite direction of inspiration.

active using abdominal wall muscles (oblique and transversus) to increase intra-abdominal pressure and depress the rib cage.

interface between gas and liquid where liquid molecules more strongly attracted to each other than gas molecules, resists increase in surface area

interferes with cohesiveness of water molecules

• 1. tidal volume
• 2. inspiratory reserve volume
• 3. expiratory reserve volume

volume during normal, quiet breathing

extra volume during forced inspiration

amount of addition air that can be expired beyond tidal volume

• total pressure of gas is the sum of pressure exerted independently by each gas.
• partial pressure; proportional to percentage of each gas in total mixture

• highest: N2 =598
• lowest: CO2= .3

760 mmHg

• When in contact with liquid, each gas will dissolve proportional to its partial pressure.
• volume of gas that will dissolve also depends of solubility

• the exchange of gases between the lungs and the pulmonary capillaries where blood gains O2 and loses CO2
• Partial pressure differences in gases drives movement

• Venous blood O2 = 40; Alveoli = 104
• Venous blood CO2 = 45; Alveoli = 40
• CO2 is more soluble than O2

• .5-1.0 um thick.
• Anything that interferes with this causes gas exchange problems (ex: pneumonia)

opposite movement of gas from external respiration

• 98% is bound to hemoglobin and the rest is dissoved in plasma
• Reduced hemoglobin binds O2 and becomes oxyhemoglobin
• oxygen-hemoglobin dissociation curve: binding of 1 molecule of O2 makes it easier to bind more O2

• binding of 1 molecule of O2 makes binding of more O2 easier
• Unloading of 1 molecule O2 enhances unloading of next
• O2 unloading accelerated at increased temperature and increased partial pressure (decreased pH); these are the responses to increased metabolism

• Anemic hypoxia- low levels of hemoglobin
• Ischemic hypoxia- exposed to less oxygen
• Histotoxic hypoxia- exposure to cyanide gas
• Hypoxemic hypoxia- CO poisoning

• 10% dissolved
• 30% bound to carbaminohemoglobin
• 60% carbonic acid and bicarbonate ions

• The lower the partial pressure of O2 and hemoglobin saturation, the more carbon dioxide is carried in blood.
• this is because O2 and CO2 are competing for binding sites

• Medullary Respiratory Centers
• Pons Respiratory Centers

• 1. Dorsal respiratory group
• 2. ventral respiratory group

• 1. Pneumotaxic center
• 2. Apneustic center

• part of the Medullary respiratory centers
• integrates signals from peripheral receptors

• part of the Medullary respiratory centers
• rhythm generating and integrative center

• part of the Pons respiratory centers
• modifies action of ventral respiratory group; can slow breathing

• Part of the Pons respiratory centers
• Hypothesized
• thought to stimulate the pneumotaxic center

• rise in blood CO2
• low blood CO2

no breathing

• depth and rate of breathing increase
• slow and shallow breathing

air sacs; air moves from nostrils into posterior air sacs, lungs, anterior air sacs and is then expired. complete cycle takes 2 inhalations/ exhalations.