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Physiology 202 > Unit 2 Lecture > Flashcards

Unit 2 Lecture Flashcards

1
Q

What are the cells of the body serviced by?

A

2 fluids: Blood and intersticial fluid

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2
Q

What is the track of nutrients, oxygen, and waster?

A

Nutrients and oxygen diffuse from the blood into the interstitial fluid and then into the cells. Waste moves in the opposite direction

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3
Q

Define hematology

A

Hematology is the study of blood an dlood disorders

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4
Q

How does blood flow through the body?

A

Oxygen mainly flows through the body by diffusion from high concentration to low concentration or oxygen can get caught up in bulk flow

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5
Q

What are the two main components of blood?

A
  1. Plasma, a clear straw colored watery liquid that consists of 91.5% water and 8.5% solutes
  2. Formed elements, which are cells and cell fragments
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6
Q

Discuss Blood Plasma

A
  • Over 90% water
  • ~7% plasma proteins
    • Created in the liver
    • Confined to bloodstream
    1. Albumins maintain blood osmotic pressure
    2. Globulins (immunoglobulins)
      • Antibodies which bind to foreign substances called antigens
      • Form antigen-antibody complexes
    3. Fibrinogens for clotting
  • ~2% other substances:
    • Electrolytes, nutrients, hormones, gases, wastes
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7
Q

What do antibodies do?

A

Antibodies tag things as foreign which then alerts white blood cells to come and eat the foreign cells

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8
Q

What is the difference between blood plasma and blood serum?

A

Blood plasma contains fibrogen and clotting factors whereas blood serum lacks clotting factors including fibrinogens

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9
Q

Discuss Formed Elements of Blood

A
  • Red Blood Cells (erythrocytes) 99% of blood volume
  • White Blood Cells (leukocytes)
    • Granular
      • Neutrophils
      • Eosinophils
      • Basophils
    • Agranular
      • Lymphocytes = T cells, B cells, and natural killer cells
      • Monocytes
  • Platelets (special cell fragments)
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10
Q

What type of stains do the granular leukocytes respond to?

A
  • Neutrophils respond to neutral stains
  • Eosinophils respond to acidic stains
  • Basophils respond to basic stains
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11
Q

What do lymphocytes do?

A

They go through the body and decide if cells or things are you or if something is foreign and then they destroy it

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12
Q

Study the flow of -blast, -cytes, and -phils from the original pluripotent stem cell

A
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13
Q

What is Erythropoietin?

A

Erythropoietin (EPO) is a hormone which stimulates production of erythrocytes

-a process termed Erythropoiesis

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14
Q

Discuss Platelets

A
  • Thrombocytes
  • The major function of platelets is blood clotting
  • Platelets are irregular shaped cell fragments, with a diameter of about 2-4 micrometers
  • There are about 150,000-400,000 platelets per microliter of blood
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15
Q

What is Hematocrit?

A
  • Is percentage of blood occupied by RBCs
    • Female normal range is 38-46% (42% is average)
    • Male normal range is 40-54% (46% average)
    • Testosterone -> EPO synthesis
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16
Q

What is anemia?

A

Not enough RBCs (or not enough hemoglobin) for proper O2 transfer

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17
Q

What is Polycythemia?

A
  • Having an excess of RBCs (over 65%)
  • Dehydration, tissue hypoxia, blood doping in athletes
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18
Q

What is blood doping?

A

Blood doping: collecting one’s own blood and draining off the top portion after centrifuging then put it in the freezer. When its game day you then inject the RBCs and you are at a better training state than other competitors because of better oxygen transport

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19
Q

Study the components of blood in your body

A
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20
Q

Discuss Erythrocytes

A
  • Erythrocytes are shaped like biconcave discs
  • This increases the surface area availabke for oxygen binding
  • Have an average diameter of ~8micrometers
  • Have no nucleus
    • They have no DNA
  • Are filled with hemoglobin, a protein that carries oxygen
  • They have no organelles because they have all been spit out
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21
Q

Discuss the shape of the red blood cell

A
  • Biconcave discs with ~8 micromete diameter
  • They are easily deformed and can change shape
    • They are stacked (rouleaux formation in larger blood vessels as seen on the right
    • “Parachute” shapes in small arterioles and venules
    • “Bullet” shapes in capillaries
      • These “parachute” and “bullet” shaped blood cells come from the cells wrapping around droplets of plasma in the vessels. The shapes are made so that there is more walled surface area for oxygen and gas exchange
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22
Q

What is hemoglobin composed of?

A
  • 4 large protein chains (2 alpha and 2 beta chains)
  • A heme group (contained within each chain)
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23
Q

Discuss the heme group on each of the 4 hemoglobin protein chains

A
  • Its a porphyrin ring that surrounds a single iron atom
  • Each iron in heme can bind one molecule of oxygen (O2) for a total of 4 molecules of O2 per Hb protein
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24
Q

What are the functions of Hemoglobin?

A
  • Each hemoglobin molecule can carry 4 O2 molecules
  • Oxygen is bound by hemoglobin (in RBCs in blood) in the capillaries of the lung and transported to the body’s cells by systemic circulation
  • Hemoglobin also transports 23% of the total CO2 produced in tissue cells; the CO2 binds to amino acids in the globin portion of hemoglobin (Hb), NOT with heme
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25
Q

What are the concentrations of Hemoglobin in Blood?

A
  • 16 g/dL (g/100mL) of blood in men
  • 14 g/dL (g/100mL) of blood in women
  • The hematocrit and the hemoglobin level are diagnostic for anemia
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26
Q

What is Erythropoiesis?

A

RBC formation

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27
Q

Describe the steps of erythropoiesis

A
  • Occurs in the red bone marrow
  • RBCs are formed from a lineage of precursor stem cells
  • Precursor myleoid stem cells differentiate into proerythroblasts
  • Proerythroblasts then become erythroblast then reticulocytes
  • When a reticulocyte reaches maturity, hemoglobin is produced and the nucleus is ejected, resulting in the formation of a mature erythrocyte
    • The nucleus with undergo phagocytosis
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28
Q

Where does erythropoiesis occur?

A

In red bone marrow

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29
Q

What is the role of hemopoietic growth factors and what are the two main ones?

A
  • Role: regulation of differentiation and proliferation of blood cells
  • Erythropoietin (EPO)
    • Stimulates erythropoiesis
    • Produced by the kidneys
      • Because the kidneys receive 25% of the blood at rest and they remove waste and produce urine
    • Increases RBC precursors
  • Thrombopoietin (TPO)
    • Hormone from liver
    • Stimulates platelet formation
  • Cytokines
    • Local hormones of bone marrow
    • Produced by some marrow cells to stimulate proliferation in other marrow cells
    • Colony-stimulating factors (CSFs) and interleukins stimulate WBC production
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30
Q

What are some medical usages of Growth Factors?

A
  • Available through recombinant DNA technology
    • Recombinant erythropoietin (EPO) is very effective in treating decreased RBC production of end-stage kidney disease
    • Other products given to stimulate WBC formation in cancer patients receiving chemotherapy which kills bone marrow
    • Thrombopoietin (TPO) helps prevent platelet depletion during chemotherapy
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31
Q

What is the life cycle of erythrocytes?

A
  • RBCs live only 120 days
    • Weat out from bending to fit through capillaries
    • No repair possible due to lack of nucleus
      • Also, since they don’t have a nucleus they won’t get as destroyed when they are crashed into
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32
Q

What happens with worn out red blood cells?

A
  • Worn out red blood cells are removed by fixed macrophages in the spleen and liver
    • Breakdown products are recycled
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33
Q

What is the overview of destruction and recycling of RBCs?

A
  • Destruction and recycling of RBCs is done by macrophages of the liver and spleen
    • Globin portion broken down into amino acids and recycled
    • Heme portion split into iron (Fe3+) and biliverdin (green pigment)
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34
Q

Discuss the function of iron after the RBC is destructed

A
  • Iron is transported in blood attached to transferrin protein
  • Stored in liver, muscle or spleen (attached to ferritin or hemosiderin protein)
  • Transported to bone marrow for use in hemoglobin synthesis
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35
Q

Discuss the function of Biliverdin after the RBC is destructed

A
  • Biliverdin (green) converted to bilirubin (yellow)
    • Bilirubin is secreted by liver as part of bile, and bile is secreted into the intestine for use in digestion
    • Bile breakdown products are excreted via kidneys and intestine
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36
Q

What is the track for biliverdin after it is finally converted to bilirubin?

A

Bilirubin is converted in the large intestine into urobilinogen. Some urobilinogen is reabsorbed, converted into urobilin, and then excreted vis the kidneys in urine

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37
Q

Discuss the basics of White Blood cells

A
  • All WBCs (leukocytes) have a nucleus, but no hemoglobin
    • Contain DNA
  • Granular or Agranular classification based on presence of cytoplasmic granules made visible by staining
    • Granulocytes are neutrophils, eosinophils and basophils
    • Agranuloctes are monocytes and lymphocytes
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38
Q

What is the ration between WBCs and RBCs

A

1 WBC for every 700 RBC

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39
Q

What is leukocytosis and leukopenia? What is the normal % of WBC in blood at any given time?

A
  • Leukocytosis is a high white blood cell count
    • Microbes, strenuous exercise, anesthesia or surgery, Stress hormones, and fighting infections
  • Leukopenia is low white blood cell count
    • Radiation, shock or chemotherapy
    • Destroy precursor cells so leukocytes won’t even be able to develop
  • Only 2% of total WBC population is in circulating blood at any given time
    • Rest is in lymphatic fluid, skin, lungs, lymph nodes and spleen
      • They eat dust and ash in the lungs
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40
Q

What is WBC emigration?

A
  • WBCs roll along endothelium, stick to it, and squeeze between cells
    • Adhesion molecules (selectins) help WBCs stick to endothelium
      • They are basically hooks on the walls of the vessels
    • They are displayed near the site of injury
    • Integrins found on neutrophils assist in movement through wall
      • Integrins get stuck on the selectins and help them move
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41
Q

What is phagocytosis? What steps are involved?

A
  • “cell eating” of bacteria
  • Performed avidly by monocytes and neutrophils
    • Macrophages identify foreign particles or bacteria
  • Eosinophils have weaker phagocytic activity
  • The process involves: chemotaxis; adherence and ingestion; and destruction
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42
Q

Describe the chemotaxis step in phagocytosis

A
  • It is the attraction of phagocytic cells to the site of infection
  • Chemicals released by the pathogen and/or the infected cell attract the phagocytes
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43
Q

Describe the Adherence and Ingestion step in phagocytosis

A
  • Adherence is the attachment of the phagocyte to the pathogen’s membrane
  • Ingestion is facilitated by enveloping pseudopodia, resulting in a phagosome
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44
Q

Describe the destruction step of phagocytosis

A
  • Destruction is initiated when the phagosome fuses with a lysosome, resulting in a “phagolysosome”
  • Lysozymes and other destructive chemicals from the lysosome destroy the membrane and internal structures of the pathogen
  • Residual fragments of the dead pathogen can be removed from the cell by exocytosis
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45
Q

Explain the clinical application of use of a bone marrow transplant including the procedure

A
  • Intravenous transfer of healthy bone marrow
  • Procedure
    • Destroy sick bone marrow with radiation and chemotherapy
    • Put sample of donor marrow into patient’s vein for reseeding of bone marrow
    • Success depends on histocompatibility of donor and recipient
  • Treatment for leukemia, sickle-cell, breast, ovarian or testicular cancer, lymphoma or aplastic anemia
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46
Q

How long do platelets live for and where do they reside?

A
  • Cell fragments that circulate for 5-9 days, then die
  • 2/3 of mature platelets circulate, whereas 1/3 reside in the spleen
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47
Q

Define thrombosis

A

Thrombosis refers to clot formation; a clot is caleed a thrombus

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48
Q

Define embolus

A

An embolus is a circulating clot

**A pulmonary embolism is a stroke and can cause a heart attack

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49
Q

Define hemorrhage

A

Hemorrhage is defined as severe, uncontrolled bleeding

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50
Q

What is Thrombocytopoiesis?

A
  • Myeloid stem cells produce megakaryocytes
  • They have a diameter of 160 micrometers
  • Thrombopoietin, or TPO, causes fragments to slough off the megakaryocyte
    • 2000-3000 fragments, or platelets, enter the circulation
  • Each platelet is roughly 2-4 micrometers in diamere and about 1 micrometer in thickness
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51
Q

Define Hemostasis and what are its three stages?

A
  • A series of reactions designed for stoppage of bleeding
  • During hemostasis, three phases occur in rapid sequence
    1. Vascular spasm - immediate vasoconstriction in response to injury
    2. Platelet plug formation
    3. Coagulation (blood clotting)
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52
Q

Describe Step 1 of hemostasis: Vascular spasm

A
  • Occurs only in vessels with smooth muscle in wall
  • Reaction to injury
  • Reduces velles diameter
  • Stops blood flow almost instantly
  • Effective only in small vessels
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53
Q

What is vascular resistance?

A
  • Blood flow is proportional to the driving pressure, and inversely proportional to the “resistance” to flow
    • Flow = driving pressure / Resistance
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54
Q

Describe step 2 of hemostasis: Platelet plug formation

A
  • Platelets NORMALLY do not stick to each other or to the endotherlial lining of blood vessels
  • Upon damage to a blood vessel, platelets:
    • Stick to exposed collagen fibers and are activated, allowing them to stick to one another
  • Phosphoserine from the injury makes the platelets sticky other than that they are never sticky
    • The Platelets also release ADP which makes it sticky and help in the formation of the platelet plug
  • Liberate thromboxane A2, serotonin and ADP, which attract and activate still more platelets
  • Release ADP which makes platelets sticky, while thromboxane A2 and serotonin cause cell contraction. This results in the formation of a tight platelet plug
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55
Q

Describe step 3 of hemostasis: Blood clotting (coagulation)

A
  • Very complex (about 30 substances)
  • 13 clotting factors (most from your liver)
  • A set of reactions in which blood is transformed from a liquid to a gel
  • Has intrinsic and extrinsic pathways
  • Intrinsic pathway tends to be slower than extrinsic pathway
  • The final 3 steps constitute the “common pathway” which must be completed in order for effective clotting to occur
    • Once prothrombinase is activated, it converts prothrombin into thrombin
    • Thrombin has two main functions
      • Converts fibrinogen (soluble) to fibrin (insoluble, stable threads)
      • Activates factor XIII, which stabilizes the fibrin network
56
Q

What is the difference between the intrinsic and extrinsic pathway for coagulation?

A
  • Intrinsic pathway is an internal injury with a cell missing exposing the basement membrane or something
  • Extrinsic pathway is an external injury with a cut exposing to the inner core of the vessel
57
Q

Look at the formation of clotting factors page

A
58
Q

Describe what fibrinolysis is

A
  • Clots must be dissolved so that they do not enter the circulation as an ambolus
  • The dissolution of a clot is known as fibrinolysis
  • Tissue plasminogen activator, thrombin and plasminogen all react to form plasmin, which then digests the fibrin strands and breaks the clot
59
Q

What are the 6 functions of the respiratory system?

A

***Angiotensin 1 is in the pulmonary cells that turn into angiotensin 2

Angiotensinogen is made in the liver and that’s what Angiotensin 1 comes from

60
Q

How does the respiratory system change the pH of blood?

A
  • The fastest way to change the pH of blood is to either hold your blood or breathe to fast
    • -Breath to fast, lost too much CO2 and become basic
    • -Hold breath, maintains and increases CO2, and becomes acidic
61
Q

What is the difference between external and internal respiration?

A
  • External respiration refers to the exchange of gases between the atmosphere and blood
    • Occurs in pulmonary capillaries and alveoli
  • Internal respiration refers to gas exchange between capillary blood and the cells in tissues
    • Occurs in pulmonary capillaries, oxygen goes out CO2 is picked up
  • BTW: Cellular respiration refers to the use of oxygen by cells to produce ATP by oxidizing glucose
    • Oxygen takes the old not very useful already used electrons so that new useful ones can come in
62
Q

Memorize the anterior view of the major organs of respiration

A
  • Stratified squamous in the Laryngopharynx
  • Pseudostratified columnar epithelium in the Naspharynx
63
Q

Memorize the face respiratory structures

A
64
Q

Memorize the anterior and posterior view of the larynx

A
65
Q

Memorize the features of the vocal cords

A
66
Q

Trace and label the “bronchial tree” starting with the trachea and terminating in the alveoli

A
67
Q

Define Pulmonary ventilation

A
  • Pulmonary ventilation: refers to the alternating flow of air into and out of the lungs
    • This cyclic airflow is due to the actions of various respiratory muscles
68
Q

Define inspiratory muscles

A
  • Inspiratory muscles: expand the rib cage during inspiration and drive airflow into the lungs
    • Inspiration increasts the diameter of the thoracic cavity this also helps with the respiratory pump of blood
69
Q

Define expiratory muscles

A
  • Expiratory muscles: depress the rib cage and force air out of the lungs
70
Q

What is the thoracic cage and what does it contain?

A
  • The skeletal portion of the thorax is called the thoracic cage
    • It includes the ribs, costal cartilages, thoracic vertebrae, and sternum
71
Q

Define respiratory mechanics

A
  • Respiratory mechanics is the study of how the respiratory muscles move the rib cage
72
Q

What is the “respiratory pump”

A
  • The “respiratory pump” refers to the respiratory muscles, rib cage, pleural membranes, and lung elastic tissues
73
Q

What is the diaphragm?

A

Diaphragm is the primary inspiratory muscle

74
Q

What do the external intercostal muscles do?

A

External intercostal muscles move ribs upward and outward, expanding the rib cage.

75
Q

What does the sternocleidomastoid do?

A

The sternocleidomastoid elevates the sternum

76
Q

What does the scalenes do?

A

The scalenes elevate the top two ribs

77
Q

What do the internal intercostals do?

A
  • Internal intercostal muscle pull ribs downward and inward, reducing the diameter of the rib cage
    • Reduce thoracic cavity volume to force air out of lungs
78
Q

What do abdominal muscles do?

A
  • Abdominal muscles depress the lower ribs and elevate the diaphragm by increasing abdominal pressure
    • Reduce thoracic cavity volume to force air out of lungs
79
Q

What does breathing and ventilation depend on?

A

Breathing, or ventilation, depends on periodic pressure changes in the lungs

80
Q

When does inspiration/inhalation occur?

A

Inspiration/inhalation occurs when pressure in the lungs becomes lower than the pressure in the atmosphere

-During inspiration, the parietal pleura is pulled outward, and the visceral pleura – and lungs – move with it

81
Q

When does expiration/exhalation occur?

A

Expiration/exhalation occurs when pressure in the lungs is high than the pressure in the atmosphere

82
Q

What do pressure changes in the lungs depend on?

A

Pleural membranes

83
Q

What is boyles gas law?

A
  • Increasing the volume decreases the pressure
    • Fewer collisions
  • Decreasing the volume increases the pressure
    • More collisions
84
Q

Look at the normal pressure changes during inhalation and exhalation

A
85
Q

What are the elastic properties of respiratory structures?

A
  1. Lung tissue will always rapidly collapse inward
    1. This is why punctures are incredibly dangerous
    2. We are always pushing a lot of force to keep the lungs inflated
  2. Chest wall will always spring outward
  3. Between breaths, the recoil forces are equal and the respiratory muscles are at rest
86
Q

What is end-expiratory lung volume

A

Physiologists define the amount of air present in the lungs in this state as the “end-expiratory lung volume” (also called functional residual capacity or FRC)

87
Q

What is transpulmonary pressure? How do you calculate it?

A
  • Transpulmonary pressure (Ptp) = distending pressure exerted on (i.e. experienced by) the lungs
  • Ptp is calculated by subtracting the intra-pleural pressure (Pip), the fluid pressure in the pleural cavity (space) which surrounds the lungs, from the air pressure inside the alveoli, called the intra-alveolar pressure (Palv)

Ptp = Palv - Pip

88
Q

Look at transpulmonary pressure within the lung

A
89
Q

Summarize the pressure changes during inhalation

A
  1. Contraction of diaphragm enlarges the thoracic cavity (increasing its volume)
  2. Parietal pleura is pulled outward, which pulls on the pleural fluid and “enlarges” the intra-pleural space, lowering the intra-pleural pressure (Pip)
  3. Lower Pip “pulls” the visceral pleura and lungs outward, enlarging the volume of the lungs and decreasing the pressure inside (the alveolar pressure of Palv)
  4. Air flows down the pressure gradient: atmosphere -> lungs
90
Q

Summarize the pressure changes during exhalation

A
  1. As the diaphragm relaxes, the Pip falls
  2. Lower Pip allows elastic tissues in each lung “ recoil inwards”
  3. As lungs recoil, they decrease in volume and compress the air inside, raising alveolar pressure (Palv) “above the atmospheric pressure”
  4. Air flows down the pressure gradient: lungs -> atmosphere
91
Q

Summarize the pressure change at rest

A
  1. Once the diaphragm is relaxed, the recoil force of lung elastic tissues is equally opposed by the opposite recoil force of the thoracic cage
  2. The alveolar pressure (Palv) is now equal to atmospheric pressure
  3. Air does not move because there is no pressure gradient: lungs <-> atmosphere
92
Q

What happens in the period between breaths? “end-expiratory lung volume”

A
  1. Chest wall recoils outwards
  2. Elastic lung tissue recoils inward
  3. Palv = atmospheric pressure
  4. Pip < atmospheric pressure
  5. Ptp is still positive (healthy elastic lung tissue is always more distended than it would prefer to be)

**Also, physiologists define the amount of air present in the lungs in this state as the “end-expiratory lung volume” (also called functional residual capacity or FRC)

93
Q

What is End-expiratory lung volume?

A

2 liters

94
Q

What does a spirogram measure?

A

The spirogram is used to measure: vital capacity, residual volume, expiratory reserve volume, tidal volume, inspiratory reserve volume, inspiratory capacity, and total lung capacity

95
Q

What does FRC define?

A
  • FRC (function residual capacity) defines the volume that fresh air must mix with in order to increase lung oxygen stores, and decrease lung carbon dioxide stores
    • Large FRC = labored breathing
    • Small FRC = large fluctuations in O2 and CO2
96
Q

What is lung compliance and what can increase and decrease it?

A
  • Lung compliance refers to the ease at which the lungs can be inflated
    • Compliance = (delta)VL / (delta)Ptp
    • Thickening or stiffening of lung tissue by disease, such as asbestosis, decreases the compliance
    • Emphysema increases compliance and raises FRC
97
Q

What is anatomic (respiratory) dead space?

A
  • The amount of air that doesn’t reach the actual lungs to mix with alveolar air
    • out of 500ml tidal breath, only 350mL reaches alveoli to mix with alveolar air
    • The remaining 150mL fills the upper respiratory system, larynx, trachea and bronchi through which no gas exchange occurs
98
Q

What is pulmonary ventilation vs. alveolar ventilation?

A
  • Pulmonary ventilation is a measure of the rate of lung ventilation
    • Pulmonary Ventilation (L/min) = tidal volume (L/breath) x breathing frequency (breaths/min)
  • Alveolar ventilation is a measure of the rate at which air actually ventilates the alveoli
    • Alveolar Ventilation (L/min) = (tidal volume - dead space volume) (L/breath) x breathing frequencey (breaths/min)
99
Q

What is partial pressure?

A
  • In a mixture of gases, each gas will exert a pressure that is proportuonal to its concentration (Dalton’s Law)
  • The pressure exerted by each gas will be a function of the total gas pressure (the atmospheric pressure in our case)
100
Q

Look at the partial pressure of Oxygen and nitrogen in out atmosphere

A
101
Q

What are the amounts of partial pressure of oxygen and carbon dioxide in our arterial and pulmonary arterial blood?

A
102
Q

When 500mL fresh air enters the lungs and mixes with FRC, how do oxygen and carbon dioxide concentrations change?

A
  • The [O2] in the alveroli is increased slightly and the [CO2] is decreased slightly, but average alveolar values do not change very much
    • The volume of fresh gas inhaled is relatively small compared to the volume already present in the lungs (the FRC) 2400mL
103
Q

Compare expired and inspired air concentrations and why they are what they are

A
  • Expired air has a lower O2 concentration and a higher CO2 concentration than the inspired air
    • This is because the O2 is removed from the lungs by the blood during inspiration
    • At the same time, CO2, which is produced in the tissues, moves from the blood to the lungs and is exhaled
104
Q

What happens in the tissues with O2?

A
  • O2 leaves the capillaries and diffuses into the cells
  • CO2 prodcued in the tissues enters the capillary
    • Because of this, venous blood has relatively low [O2] and high [CO2]
105
Q

Why is CO2 necessary for partial pressure in our blood?

A

It is a buffer for acid/base pH changes in our blood

106
Q

Memorize the partial pressure levels in the track from oxygenated blood to deoxygenated blood through the lungs and tissues of the body

A
107
Q

What are the typical values for O2 consumption and CO2 production? What does glucose become and what does O2 become during cellular respiration?

A

O2 consumption (mL/min) Rest: 250 Max Ex: 3500

CO2 production (mL/min) Rest: 200 Max Ex: 3800

108
Q

What is the respiratory quotient (RQ)?

A
  • The amounts of oxygen consumed and carbon dioxide produced are not equal
  • The amount of CO2 produced divided by the O2 consumed represents the respiratory quotient
  • The “RQ” varies with the type of nutrient being used by the cell
  • For pure fat, RQ = 0.7
  • For pure carbohydrate, RQ = 1.0
109
Q

What are the two ways in which O2 is transported?

A
  1. Dissolved in the plasma (about 1.5% of the total)
  2. bound to the protein hemoglobin (about 98.5% of the total)
110
Q

What does the extent to which O2 binds depend on?

A

It depends on the PO2 in the plasma

-The relationship between the extent of oxygen binding to hemoglobin and PO2 is described by constructing an “oxy-hemoglobin dissociation curve”

111
Q

Discuss the Oxy-Hemoglobin dissociation curve

A
  • Shows that the binding and release of O2 from hemoglobin is critically dependent on the PO2
  • Lung PO2 exceeds the PO2 in the blood that is entering the pulmonary capillaries (the “mixed venous blood”)
  • O2 then diffuses into blood and binds to hemoglobin
  • Tissue PO2 is low, resulting in the release of O2 from hemoglobin
112
Q

What is the “Bohr shift”?

A

A reduction in blood pH, and increases in blood PCO2 and increase in temperature causes the curve to shift to the right

113
Q

What is the importance of the Bohr shift?

A

It is that the hemoglobin molecules will release more oxygen at any given PO2

114
Q

Where is the Bohr shift most important?

A

This is most important at tissue capillaries because the hemoglobin in blood flowing through these vessels will release oxygen more readily

115
Q

What are three hallmarks of metabolic tissue?

A
  • Higher temperature
  • CO2 levels go up
  • The more CO2 you dissolve, the more acidic the blood is
116
Q

What is the effect of pH on affinity of hemoglobin for oxygen

A

As pH decreases, the affinity of hemoglobin for oxygen declines, so less O2 combines with hemoglobin and then more O2 is available for the tissures

117
Q

What is the effect of PCO2 on Affinity of Hemoglobin for oxygen?

A

As Pco2 increases, the affinity of hemoglobin for oxygen declines, so less O2 combines with hemoglobin and then more O2 is available for the tissures

118
Q

What is the effect of Temp on affinity of hemaglobin for oxygen?

A

As temperature increases, the affinity of hemoglobin for O2 decreases

119
Q

What happens when the CO2 is released from active tissue cells?

A

It diffuses into the plasma and then into RBCs

  • In RBCs both H2CO3 and “carbaminohemoglobin” are formed
  • about 70% of the total CO2 is transported in plasma as bicarbonate ions
  • About 23% of the CO2 transported is carbaminohemoglobin
  • About 7% of the CO2 transported is dissolved in plasma
    • The above products are made in RBCs by CO2 and then spit out into the plasma
120
Q

What is the carbonic acid formation and transport as “bicarbonate” reaction?

A

**This is why CO2 makes things in the body more acidic because of the H+

121
Q

Study the percentages of the different CO2 and O2 transports

A
122
Q

Try to understand internal respiration and the chloride shift across RBCs

A

CO2 diffuses out of tissue cells that produce it and enters red blood cells, where some of it binds to hemoglobin, forming carbaminohemoglobin (Hb–CO2). This reaction causes O2 to dissociate from oxyhemoglobin (Hb–O2). Other molecules of CO2 combine with water to produce bicarbonate ions (HCO3−) and hydrogen ions (H+). As Hb buffers H+, the Hb releases O2 (Bohr effect). To maintain electrical balance, a chloride ion (Cl−) enters the RBC for each HCO3− that exits (chloride shift).

123
Q

Try to understand the external respiration and the reversal chloride shift across RBCs

A

As carbon dioxide (CO2) is exhaled, hemoglobin (Hb) inside red blood cells in pulmonary capillaries unloads CO2 and picks up O2 from alveolar air. Binding of O2 to Hb–H releases hydrogen ions (H+). Bicarbonate ions (HCO3−) pass into the RBC and bind to released H+, forming carbonic acid (H2CO3). The H2CO3 dissociates into water (H2O) and CO2, and the CO2 diffuses from blood into alveolar air. To maintain electrical balance, a chloride ion (Cl−) exits the RBC for each HCO3− that enters (reverse chloride shift).

124
Q

What is “Transit Time” in pulmonary capillaries and how long does it take?

A
  • Oxygen loading at the pulmonary capillary is a time dependent process
  • It depends on the rate of gas diffusion, and the rate of blood flow through the pulmonary capillaries…or “transit time”
  • In a healthy lung, complere diffusion of oxygen occurs in about 0.25 seconds in most alveolar-capillary units
  • Transit time at rest is about 0.8 seconds, so there is plent of time for oxygen diffusion
125
Q

What are respiratory muscles and how do they contract?

A
  • The respiratory muscles are skeletal muscles, and therefore they must be made to contract by the action of motor neurons
  • Unlike other skeletal muscles, the respiratory muscles are under both automatic and voluntary control
126
Q

What does automatic respiratory control depend on?

A

Automatic respiratory muscle control depends on groups of inspiratory and expiratory neurons in the medulla oblongata

127
Q

What is the difference between inspiratory and expiratory neurons?

A
128
Q

Discuss respiratory “rhythm generation”

A
  • Breathing is rhythmic and depends on “pacemaker-like” activity in brain stem neurons that alternately turn the inspiratory neurons on and off
  • Expiratory neurons are generally silent at rest, but are activated when breathing activity must
129
Q

What do your pneumotaxic and apneustic areas do?

A
130
Q

What happens during normal quiet breathing at the inspiratory area?

A
131
Q

What happens during forceful breathing at the inspiratory and expiratory areas?

A
132
Q

What do the respiratory neurons depend on?

A

They depend on information from various specialized receptors that inform the neurons about the body’s needs for ventilation

  1. Pulmonary stretch receptors
  2. Central chemoreceptors
  3. Peripheral chemoreceptors
133
Q

Discuss pulmonary stretch receptors

A
  • Receptors are located in the smooth muscle that lines some of the large conducting airways, bronchi and bronchioles
  • They respond when bronchioles are inflated or stretched
  • The main stimulus appears to be the rate of change of lung stretch
  • The receptors are innervated by axons in the vagus nerve (CN X)
134
Q

Discuss central chemoreceptors

A
  • Receptors are located just beneath the ventral surface of the medulla
  • They respond to low pH and high Pco2 in the cerebrospinal fluid (CSF)
  • Low pH in the CSF is the result of CO2 that diffuses into the CSF from the blood and forms hydrogen ions (this is when we start breathing faster)
  • This is why central chemoreceptors are call “CO2 sensitive receptors”
135
Q

Discuss peripheral chemoreceptors

A
  • Peripheral chemoreceptors are located in the aortic arch and in the carotid sinus
  • These receptors respond to low levels of oxygen in the arterial blood (that is heading to the brain)
  • They also respond to low pH, and high carbon dioxide levels, but weakly
  • These receptors are innervated by axons that travel in CN IX (glossopharyngeal nerve) and X (vagus nerve) and synapse on neurons in the DRG
136
Q

Summarize the influences of respiration

A
137
Q

What happens with CO2 when we are running?

A

On a run, CO2 starts increasing, air pH decreases, so we need to breathe more

Physiology 202 (12 decks)

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