Lecture 3 Exam Flashcards
Compare and contrast the circulatory system and cardiovascular system.
Circulatory system:
- The network that transports nutrients gases and waste throughout the body including blood, vessels, and the heart Also helps regulate body temperature
Cardiovascular system:
- The heart and the vessels it uses to pump blood to maintain homeostasis
What are the components of blood?
Erythrocytes (RBC):
- Transporters of O2 and CO2
Leukocytes (WBC):
- Immune cells that fight off antigens
Thrombocytes (Platelets)
- Responsible for blood clotting
Plasma
- Liquid portion of blood containing water, nutrients, proteins, waste and more
What is hematocrit?
- The percentage of blood volume that is RBC
- Measured via centrifugation
- Helpful for diagnosing anemia or polycythemia
- 48-52% in men, 37-48% in women
Compare plasma and whole blood
Plasma:
- Fluid component of blood
- 90% water, contains ions, nutrients, waste, and proteins
- Albumin (osmotic pressure, viscosity), Globulins (iron, antibodies, lipid transport), Fibrinogen (blood clotting)
Whole:
- Includes plasma in addition to packed cells which are RBC, WBC, and thrombocytes
What proteins are found in plasma?
Albumin - Contributes to osmotic pressure and viscosity
Globulin - Antibodies and transport of lipids, iron and copper
Fibrinogen - Blood clotting
Differentiate between granulocytes and Agranulocytes.
Based on presence or absence of granules
Granulocytes
- Neutrophils, eosinophils, basophils
Agranulocytes
- Lymphocytes and monocytes
Rank the WBC in order of abundance
Granulocytes:
- Neutrophils (40-70)
- Eosinophils (1-4)
- Basophils (0-1)
Agranulocytes:
- Lymphocytes (20-45)
- Monocytes (4-8)
What are structural and functional features of RBCs
Structure
- Hemoglobin can bind 4 oxygen bc of heme group
- Biconcave shape
- Lack mito, ER, nucl., and DNA
Function
- Extremely effective oxygen transported
- Shape allows for increased surface area and flexibility
What are the five classes of leukocyte and what do they do?
Neutrophils - phagocytize and destroy bact. by releasing granules
Eosinophils - Degrade histamine and release inflammatory inhibitors (parasites)
Basophils - Secrete histamines (vasodilation) and heparin (reduce clotting)
Lymphocytes - Provide protection against specific pathogens. T cells attack directly, B cells attack via proxy antibodies by becoming plasma cells
Monocytes - Become macrophages which ingest foreign cells, debris, and molecules
Describe the structure and role of platelets.
- Disc shaped, plasma membrane enclosed fragments of cytoplasm
- Plug holes in blood vessels
- Secrete vaso constrictors
- Contain procoagulants (clotting factors)
- Secrete chemicals to attract other leukocytes
Compare red and yellow bone marrow
Red:
- Involved in hematopoiesis
- Production of RBC, WBC, platelets
- Sternum, pelvis, ribs, ends of long bones
Yellow:
- Composed of adipose tissue
- Energy reserve
- Can be reverted to red marrow if needed
- Located in long bones
What is hematopoiesis? What is a hematopoietic stem cells?
- The process of a cell differentiating into either a lymphoid cell or myeloid cell. Occurs in bone marrow. Responsible for making all blood cells including red and white
- Lymphoid will provide specific protection while myeloid provides general protection
- Hematopoietic stem cells are cells that can become a myeloid cell or lymphoid cell
What is erythropoiesis?
- The differentiation of proerythroblast into erythrocytes
- Allows for red blood cells to develop
What is a thrombus? An Embolus?
- A clot that develops in an undamaged blood vessel
- When a thrombus breaks off a vessel wall and floated freely in the blood. Can obstruct vessel resulting in stroke (if brain is reached)
What is a CBC? A CBC with differential?
- Complete blood count
- Measures RBC, WBC, hematocrit, hemoglobin, platelets
- Used for diagnosing and monitoring health
- CBC with differential used to get a more detailed breakdown
Describe Anemia, sickle cell, and leukemia.
Anemia - Defficiency in RBC/hemoglobin means reduced oxygen is transported resulting in fatigue and weakness
Sickle cell - genetic disorder resulting in RBC having rigid shape causing blockages, pain, and more
Leukemia - Cancer that affects bone and bone marrow resulting in uncontrolled WBC production which interferes with normal blood function.
Identify the heart chambers, valves, septa, and blood vessels that lead to and away from the heart.
- DO blood enters right atrium via superior and inferior vena cava
- DO blood is pushed through the one way tricuspid valve into the right ventricle
- Once the chamber is filled it is pumped through the pulmonary semilunar valve into the pulmonary trunk
- The pulmonary trunk then splits into a right and left pulmonary artery to be sent to the lungs to be oxygenated
- When O blood returns to the heart to be pumped to the body it enters the heart through the pulmonary vein
- O blood enters the left atrium
- O blood is then pumped through the bicuspid valve into the right ventricle
- O blood is then pumped through the aortic semilunar valve
- The O blood is then distributed to they body and eventually becomes DO blood and returns to the hear through the inferior vena cava
Interatrial septa: separates right and left atria and comes from foramen ovale during fetal development
Interventricular septa: separates right and left ventricle and assists in pumping
(Tricuspid also known as atrioventricular)
(Bicuspid valve also known as mitrial or left atrioventricular)
What are the pericardial membranes and layers of the heart wall?
Pericardial membranes:
- Fibrous pericardium
- Parietal layer of pericardium
- Pericardial cavity
Heart Wall:
- Vesceral layer of serous pericardium
- Myocardium
- Endocardium
What is the chordae tendineae? What about papillary muscles?
Chordae tendinae:
- Fibrous cord that attach to papillary muscle to prevent backflow into the atria in the bicuspid and tricuspid valve
- Keeps valve closed during ventricular contraction
Papillary muscle:
- Small cone structures in the ventricles that serve as an attachment point for chordae tendineae
- Maintain tension so that there is no backflow of blood into the atria
What are the nodes and bundles used in conduction? What is the path of impulse?
- The heart has special autorhythmic muscle
1. Sinoatrial node (SA or pacemaker) generates an electrical impulse that travels through the internodal pathway
2. The impulse reaches the Atrioventricular node (AV) (atria contracts and fills ventricle with blood)
3. The impulse then travels through the AV bundle (bundle of His) then through bundle branches
4. The impulse then finally reaches the purkinje fibers resulting in ventricular contraction
What is systole? Diastole?
Systole:
- Heart muscle is contracted sending blood to the body and lungs
- Ventricles contract to pump blood out
- High blood pressure
Diastole:
- Heart is relaxed and the atria and ventricles are filling
- Low blood pressure
What are the actions of the sympathetic and parasympathetic nervous system on heart rate?
Sympathetic:
- Speeds up heart rate
- Dense at SA and AV node
Parasympathetic:
- Slows down heart rate
Hypothalamus sends signal based on physical conditions. Amygdala sends signals based on emotional condition. Medulla oblongata processes signals and responds accordingly
What is meant by systemic/pulmonary/cardiac circulation?
Systemic circulation:
- Blood to organs of the body
Pulmonary circulation:
- Blood to lungs
Cardiac circulation:
- The systemic and pulmonary combined
What is the function of the heart?
- To pump blood throughout the body
- Blood can carry oxygen, CO2, ions, water, nutrients, and waste
What is the coronary sulcus? What coronary vessels are found there?
- The groove that atria and ventricles have that houses important coronary artery and veins
- Coronary artery: provides heart with oxygenated blood
- Coronary sinus (multiple coronary veins) drains deoxygenated blood from the heart into the right atrium
What is the path of an oxygen molecule?
- O2 enters through the nose
- Oxygen warms and moisturizes in the vestibule in the nasal cavity
- Nasopharynx, oropharynx, largingopharynx, larynx
- enters trachea and splits at the fork (corena) where it is guided to a primary bronchi
- Enters secondary, tertiary, then broncioles
- Then reaches terminal bronchioles (end of conducting zone)
- Reaches resp bronchioles which is begining of respiratory zone
- Alveolar ducts lead to alveolar sacs which lead to alveoli
- Air then crosses three layer respiratory membrane
- Enters pulmonary capillaries
- Reverse order is for CO2
What are the anterior and posterior interventricular sulcus?
Anterior:
- Sulcus located on the front (vertically)of the heart provides blood to left ventricle and part of interventricular septum
Posterior:
- Sulcus located on the back (vertically) of the heart provides blood to both ventricles and posterior parts of interventricular septum
What are the characteristics of the right and left atria? What about the right and left ventricles? (What structures are present chordae tendineae)
Right Atrium
- Receives DO blood from Sup/Inferior vena cava
- Thin muscle wall
- Tricuspid/ right atrioventricular valve
Right Ventricle
- Fills with DO blood to send to lungs
- Thick wall
- Contains tricuspid, pulmonary semilunar valve, chordae tendineae, and papillary muscle
Left Atrium
- Receives O blood from pulmonary veins
- Thin muscle wall
- Bicuspid/mitrial/ left atrioventricular valve
Left Ventricle
- Fills with O blood to pump to body
-Thickest wall
- Contains bicuspid, aortic semilunar valve, chordae tendineae, and papillary muscle
How can blood return to the heart from the legs if veins have low pressure
- The veins have valves that ensure the blood can make its way up the body without backflow
- Muscles such as gastrocnemius can help pump blood against gravity towards the heart when skeletal muscle contracts
What are the heart sounds and what do they mean?
- Heartbeat consist of Lub-Dub sound
- Lub is the first sound and is the AV valves shutting
- Dub is the second sound and is the semilunar valves shutting
- A doctor can use a stethoscope positioned near the valves to hear if there is some type of arrhythmia
What is a cardiac cycle? Describe the order of valves closing and opening and how blood moves through the heart chambers
- Blood enters the right atrium and fills the chamber
- Blood then flows into the right ventricle via tricuspid valve
- Right ventricle will contract and close the tricuspid valve forcing the blood through the pulmonary semilunar valve
- Blood then reenters the heart (after pulmonary circuit)
- Blood fills the left atrium and drains through the bicuspid valve
- The left ventricle then contracts shutting the bicuspid valve and pumping blood through the aortic semilunar valve to be distributed to the body
What are the layers of the blood vessels and tissue found?
Tunica intima- simple squamous ET
Tunica media- circular sheet of smooth muscle(vasomotion)
Tunica externa-CT with collagen and elastin(longitudinal arrangement)
What are resistance, capacitance, and exchange vessels? What effect does diameter have on resistance?
Resistance
- Primary arterioles, small diameter arteries that lead to capillaries
- Can regulate blood flow by constricting or dilatating
Capacitance
- Mainly veins and venules have large diameter and hold a large blood volume
- Store blood and act as reservoir. Control blood volume
Exchange
- Capillaries, smallest blood vessels
- Facilitate exchange of gas, nutrients, and waste between blood and surrounding tissue
- Resistance is inversely proportional to radius. Larger vessel = lower resistance
Compare and contrast arteries and veins
Arteries
- Move blood away from heart
-3 tunicas
- Elastic to dissipate pressure
- Muscular layer allows regulation of diameter
Veins
- Move blood towards heart
- 3 tunicas
– Thick outer tunica
- Larger lumen and thinner walls
- Not capable of vasomotion
Which vessels have valves and what is their purpose?
- Veins have valves to prevent the backflow of blood
- Low pressure means blood has trouble traveling against gravity
- Skeletal muscle flexing is able to pump veins to aid in getting blood back to heart
What occurs in varicose veins?
- Blood gets stuck in dysfunctional valves resulting in blood pooling. Another cause is prolonged sitting. Either can result in blood pooling causing veins to become blue and gain a weblike appearance.
What is the order of blood flow from arteries to capillaries to veins? How thick are the tunic layers? How can you differentiate a artery and vein?
- Arteries
- Thin elastic intima, thickest media for pressure, thinner extrema for structure - Arterioles
- Similar to arteries but everything is generally the same, thinner media and externa - Capillaries
- Only have intima, composed of single layer to allow efficient exchange of gases, nutrients, and waste - Venules
- Thin intima, very thin media, and thick externa for structural support - Veins
- Thinner intima containing valves, media thinner than arteries, thicker externa composed of CT
What is anastomosis?
- A small opening that connects two structures. An example is the bypass between the right and left atria in the fetal heart
What are vasa vasorum?
- Small blood vessels that provide nutrients to the outer layers of larger vessels such as arteries and veins
What are the different types of capillaries and what is their permeability like?
Continuous
- Tight junctions
- Intercellular cleft
- Selectively permeability
- Found in muscle, lungs, CNS
Fenestrated
-Tight junctions
- Fenestration pores
- High permeability
- Kidney, intestines, endocrine glands
Sinusoids
- Tight junctions
- Large intercellular cleft
- Highest permeability
- Liver, spleen, and bone marrow
What are the routes of capillary permeability? Why does fluid enter the interstitial space?
3 routes of permeability:
Endothelial cell junctions Many cells are held by tight junctions molecules must rely on pores called fenestrae
Transcytosis When molecules such as proteins(or large molecules) are engulfed by a cell and transported to the other side
Diffusion Small nonpolar molecules (o2,co2) can diffuse through the bilayer
- Fluid enters the interstitial space due to hydrostatic pressure within capillaries pushing fluid out
- Osmotic pressure also draws fluid(solvent) into solute
Describe aorta, IVC, SVC, pulmonary trunk, arteries, veins, and coronary sinus.
Aorta
- Artery that sends oxygenated blood to the right arm, left arm, neck, head, thoracic and abdominal organs
Inferior Vena Cava
- Collects DO blood leading to the heart from legs, pelvic region, and abdominal organs
Superior Vena Cava
- Collect DO blood leading to the heart from the head, neck, upper limbs, and thoracic region
Pulmonary Trunk
- Is a fork in which blood travels to either the right or left lung after exiting the right ventricle to be oxygenated
Arteries
- Transport blood away from the heart
Veins
- Transport blood towards the heart
Coronary sinus
- Large vein that carries DO blood from the heart and drains in the right atrium
What is atherosclerosis? What is the onset, treatment, and prevention?
- Build up of plaque in arterial walls. can reduce blood flow and increase risk of stroke or heart attack
- High cholesterol, high BP, diabetes, genetic are onset
- Treatments include healthy lifestyle such as diet and exercise. Medication and surgery are also options
- Preventative measures are eating healthy exercising regularly. Avoid smoking and maintain healthy weight
What are the fetal structures of the heart and what happens to them? Which vessels carry DO and O blood?
Umbilical artery - Provides O blood to placenta
Umbilical vein - Takes DO blood back to heart
Foramen ovale - Allows oxygenated blood to skip the pulmonary system by allowing oxygenated blood to go from the right atrium to the left atrium
Ductus arteriosus - Diverts blood from the pulmonary trunk to the aorta
What is an aneurysm?
- Abnormal dilatation in the wall of a blood vessel
- caused by high blood pressure, atherosclerosis, or genetic conditions
- Found in aorta or brain
- Can rupture leading to internal bleeding
What is the function of the lymphatic system?
- Maintain fluid balance by transporting excess fluid back to the blood pool
- Return leaked nutrients, proteins, and fats
- Fight disease
What is lymph tissue fluid?
Components
- Mostly water
- Ions and gases
- Carbs and amino acids
- Proteins including antibodies and enzymes
- WBC that play a role in the immune system
- Lipids and fats
Many of these leak from capillaries and will simply be returned to the blood pool
What is the order of lymph collection in the vessels?
Capillary -> Lymph capillary -> Lymph collecting vessel -> Lymph node(s) -> (lymph vessels) -> Lymph trunk -> Lymph duct -> Drain into DO blood in the heart
What are characteristics of lymph vessels? What are their tunicas like? Where are lymph vessels not found?
- No pumps
- Valves
- More permeable allowing absorption of interstitial fluid
- Many nodes connected by lymph vessels all draining to the heart
- Intima is thin and reduces friction as lymph flows
- Media is thin and contains smooth muscle, elastic fiber fibers and allows for minor contraction and expansion
- Externa is made of CT to provide support and elasticity
- Not found in eyes, CNS, Teeth, and cartilage
What are lacteals and chyle?
Lacteals
- Specialized lymphatic vessels in the villi of small intestine
- Absorb fats, and fat soluble proteins after they’ve been broken down
- Larger and more permeable than normal lymphatic vessels
Chyle
- Milky fluid formed in lacteals when digesting fatty foods
- Consists of lymph fluid mixed with digested fats, fatty acids, and fat soluble vitamins
- travels through lymphatic system draining into thoracic duct and entering bloodstream to be absorbed as nutrients
What are the 6 trunks?
Subclavian trunks - Lymph from upper limbs
Jugular trunks - Lymph from head and neck
Lumbar trunks - Lymph from lower limbs and lumbar region
Intestinal trunks - Receives chyle from digestive organs
Bronchomediastinal trunks - Collect lymph from thoracic viscera
intercostal trunk - Drains from thoracic cage region
What are the two ducts? What do they drain and where are they?
Thoracic Duct
- Ascends along vertebral bodies
- Empties into venous circulation
- Junction of L internal jugular and L subclavian vein
- Drains 3/4 of body
Right Lymphatic Duct
- Empties into R subclavian vein at junction w/ R jugular vein
- Drains right side of head, neck, right arm, and portion of the right thorax
What is lymphoid tissue and where do you find it?
- Important tissue where lymphocytes are activated by pathogens
- Type of CT (reticular) where cells are scattered
- Mucosa-associated lymphoid tissue is adapted to protect mucosal surfaces
- Ex. Peyer’s patches in small intestine monitor bacterial growth
What are lymphoid organs what do they do and where are they found? What is primary vs secondary?
- Specialized structures that produce, develop, and activate lymphocytes
Primary:
- Bone marrow, where B cells are made
- Thymus, where T cells mature and specify
Secondary
- Lymph nodes, lymph filter and activation site
- Spleen, filters blood and responds to blood borne pathogens
- Tonsils, trap pathogens from nose and mouth
- Peyer’s patches, monitor small intestine bacteria
- Appendix, manage gut flora
What are characteristics of lymph nodes?
- Bean shaped
- Approx 500
- Not glands
- Hilus - concave side where lymph vessels enter and exit
- Afferent - Carry lymph from tissue to node
- Efferent - Carry lymph from node toward bloodstream
- Cortex outer region of lymph node where B cells are
- Medulla inner part containing B cells, T cells, macrophages
How do lymphatic vessels differ from those of the cardiovascular system? How are they similar?
Lymphatic
- Transport lymph to manage fluid, waste, immune response
- Thin walls with more valves
- Low pressure
Cardiovascular
- Transport blood, nutrients waste and more
- Thicker walls to handle pressure
- High pressure
Both
- Contain valves
- Regulate fluid (blood volume/fluid retention)
- Both lead to heart
How can a lymphocyte recognize an antigen? What is a B cell? What is a T cell? How is their function and activation different?
Lymphocytes can have a specific or nonspecific response as they will recognize Epitopes on antigens (antibodies). Additional lymphocytes can they be recruited via inflammatory mediators
- B cells are immune cells that use antibodies
- T cells are presented antigens and respond directly and through cell mediated response(complement activation)
What is an antigen/pathogen?
A foreign substance that illicit an immune response
What is edema? How does it occur? What is elephantiasis? Why do lymph nodes swell?
Edema - inability to transport fluid resulting in pooling of lymph fluid in tissue resulting in swelling
Elephantiasis - Extreme lymphedema resulting from parasite
- Lymph nodes swell as lymphocytes perforate and are recruited to a specific area
Define: pulmonary effusion, respiratory distress syndrome, atelectasis, pneumothorax, asthma, emphysema, bronchitis, obstructive disorders (COPD) and pleurisy
Pulmonary effusion - Fluid accumulation in pleura space surrounding lung
RDS - Insufficient surfactant in lungs resulting in difficulty breathing
Atelectasis - Partial or total colapse of a lung or lobe resulting in reduced gas exchange
Pneumothorax - Presence of air in Pleural space can cause lung collapse
Asthma - Chronic inflammatory disease due to bronchial hyperreactivity
Emphysema - Lung disease that damages alveoli
Bronchitis - Inflammation of bronchial tubes
COPD - obstruction in airflow interfering with normal breathing
Pleurisy - Inflammation of pleura
What are the four functions of the pulmonary system? What is respiration?
- Facilitate gas exchange between o2 and co2 and alveoli
- Regulate blood pH by expelling CO2
- Filter air and remove pathogens through mucous production
- Speech
- The process of exchanging gases between the atmosphere and an organism. Allows us to inhale air and get oxygen while expelling CO2 as we exhale. O2 allows our cells to produce energy
What are conductive vs respiratory airways?
Conductive:
- Responsible for passage of air to the lungs but no exchange
- Nasal passages, pharynx, larynx, trachea, bronchi, bronchioles
- Lined with mucous membrane
Respiratory:
- Involved in gas exchange between atmosphere and blood
- Includes respiratory bronchioles, alveolar ducts, and alveoli
- Thin airways containing alveoli where O2 and CO2 are exchanged
What is the functional unit of the lungs?
Alveoli are small ballon like structures that are surrounded by capillaries which allows for oxygen to diffuse into blood and CO2 to diffuse out
Follow the path of an oxygen molecule as it travels and reaches a capillary. Do the same for CO2.
- O2 enters via nose
- Oxygen is warmed and moisturized in the nasal cavity
- O2 travels through Nasopharynx -> oropharynx -> laryngopharynx -> larynx
- O2 enters trachea and splits at fork (Carina) to go to primary bronchi
- Enters secondary -> tertiary -> bronchiles
- Reaches terminal bronchioles (end of conducting zone)
- Reaches respiratory bronchioles (respiratory zone)
- Alveolar ducts -> alveolar sacs -> alveoli
- Air crosses three layers of respiratory membrane
- Enters pulmonary capillaries
- CO2 is the reverse order
What function does the nose serve?
- Moistens and warms air
- Filters inhaled air
- Resonating chambers for speech
- FEMS
- Frontal sinus
- Ethmoid sinus
- Sphenoid sinus
- Maxillary sinus
What types of mucous membranes do you find in the nose and what cell types are found there?
Respiratory mucosa:
- Lines most of the nasal cavity
- Ciliated columnar EC move mucous
- Goblet cells produce mucus
- Basal cells replenish EC
Olfactory mucosa:
- Found on roof of nasal cavity
- Olfactory sensory neurons detect odors and send brain signal
- Supporting cells provide structural and metabolic support
- Basal cells replenish cells
Understand the gross anatomy of the nasal cavity.
Soft palate - Muscle that closes of nasal passage when swallowing
Hard palate - Provides separation of nasal and oral cavity
Inferior concha - Increases SA for filtering, warming, and humidifying air
Middle concha - Facilitates draining sinus
Superior concha - supports olfaction
Vestible - Anterior part of nasal cavity filters large particles, (moisturize, regulate temp, filter)
Understand the gross anatomy of the pharynx
Nasopharynx:
- Top portion extending from nasal cavity to soft palate
- Contains pharynogtonsils, opening of eustachian tubes
Oropharynx:
- Middle section from soft palate to hyoid bone
- Passageway for air and food
- Contains palentine and lingual tonsils (immune)
Laryngopharynx
- Extends from hyoid level to esophagus and larynx
- Directs food and air to proper areas
What are the functions of the larynx?
- Produce voice
- Provides open airway
- Routes air and food to proper channels
What cartilage do you find in the larynx?
9 cartilages connected by membranes and ligaments
- Thyroid (Adam’s apple)
- Cricoid
- Arytenoid(2) - anchor vocal chords
- Corniculate(2) - pulled on by intrinsic muscles
- Cuneiform(2)
- Epiglottis - Protects airway
What is the glottis?
- Part of larynx consisting of vocal cords and the opening between them
- Can produce sound through tension and vibration
- Can open and close to control airflow into trachea
Know characteristics of the true and false vocal cords
True - Elastic fibers, white, avascular
False - No sound production but can accentuate high pitch
Know the gross anatomy of the trachea. Understand the three layers of it’s microscope structure
- Extends from clavicles to lower respiratory tract
- Divides into two bronchi
C-cartilage - Cartilage(hyaline) rings keep airway open despite pressure change
Carina - Marks the beginning of bronchi
(cartilage, Carina, under)
Mucosa
- ET is pseudostratified columnar epithelium containing goblet cells
- Lamina propria, CT supports epithelium (innervated, blood, immune)
Submucosa
- CT that provides additional support and contain glands, serous, mucous cells
Adventitia
- Loose CT anchors trachea providing structural support and flexibility. Contains tracheal cartilages
What are the branches of the bronchial tree?
Primary bronchi -> Secondary bronchi -> Tertiary bronchi -> Bronchioles -> Terminal bronchioles -> Respiratory bronchioles -> Alveolar duct -> Alveolar sac -> Alveoli
Describe alveoli. What two types of cells are found there? What is surfactant?
- Small chambers surrounded by elastic fibers and capillaries that have a thin cell layer to allow gas exchange
Type I: - Simple squamous epithelial cells and basal laminae
Type II: - Scattered throughout, Cuboid epithelial cells that secrete surfactant, lipids and peotein
- Repair damage
- Reduce surface tension preventing collapse during exhalation
Describe the respiratory membrane
Alveolar epithelium
Fused basal lamina
Capillary endothelium
- Thin layers allow oxygen to go from high cc to low (into blood) and CO2 to go from high cc to low (blood into alveolar space)
What is the pleural cavity and what are its membranes?
- A thin fluid filled space located between two layers of pleura that surrounds lungs
- Parietal pleura lines inner surface of chest wall
- Pleural cavity
- Visceral pleura covers the surface of the lungs
- Pleural fluid will reduce friction and create surface tension to maintain inflated lungs
What is the gross anatomy of the lungs?
Apex - Top part of lung
Base - Broad surface resting on diaphragm
Hilum - Region on medial surface where bronchi, blood vessels, and nerves exit the lung
Oblique fissure - Separates the left lung into upper and lower lob. Separates right lung into upper, middle, and lower lobes
Horizontal fissure - Horizontal fissure only on right lung
Lobules - Smaller unit of the lung which contain a cluster of alveoli, bronchioles
Left cardiac notch - Concave indentation on medial surface of the left lung accommodates the space taken up by the heart
What is ventilation vs respiration? What is the process of inhalation? Exhalation?
- Ventilation is the mechanism that allows for gas exchange
- Respiration is the process that allows for energy production through the gases exchanged
Inhalation:
- Volume in thoracic increases
- Decrease internal pressure
- Diaphragm flattens (contracts)
- External intercostals contracts (elevates ribs)
Exhalation:
- Volume in thoracic decreases
- Increase internal pressure
- Diaphragm rounds out (relaxes)
- External intercostals relax
What are the four steps of respiration?
Pulmonary ventilation: Air moves in and out of lungs (inspiration,exhalation)
External respiration: Gas exchange between blood and air at alveoli
Transport of respiratory gases: Blood (gases) must be transported to the bodies cells
Internal respiration: Gas exchange between capillaries and tissue
What is the mechanism for respiratory centers and chemoreceptors for breathing control?
Respiratory centers
- Generate baseline respiration rate
- Input from pons (hypothalamus, limbic and cerebral cortex)
Chemoreceptors
- Sensitive to rising and falling oxygen, pH, and CO2
- Central chemoreceptors are in the medulla
- Peripheral chemoreceptors are in aortic bodies and carotid bodies (CN IX via vagus)
- Brain will realize that CO2 build up is high and make you start to exhale quicker
What are the sympathetic and parasympathetic effects on lungs function?
Parasympathetic:
- Promotes bronchoconstriction (closing)
- Narrow airways when resting allows conservation of energy (Vagus nerve, acetylcholine)
Sympathetic:
- Promotes bronchodilation (opening)
- Wider airways during intense excersise to meet high O2 demands (sympathetic nerve, norepinephrine)
