Comparative Vertebrate Physiology
Download
Report
Transcript Comparative Vertebrate Physiology
Human Anatomy and
Physiology
Blood and hemodynamics
Blood composition
Plasma and formed elements
Formed elements
Erythrocytes, leukocytes, platelets
Blood composition
Hematocrit
<45% anemia (O2 delivery problems)
>45% polycythemia (circulation problem)
Plasma
Contents
90% water
Protein (albumin acts as a buffer)
Fats, amino acids, salts, gases, enzymes,
hormones
Narrow osmolality range
Erythrocytes
Manufactured by erythropoiesis
Committed cell: will form a specific cell type
Erythroblasts undergo rapid mitosis
Reticulocytes enter blood stream (2% of blood)
Erythropoiesis
Erythrocytes
Function: gas exchange
Oxy- and deoxyhemoglobin
Erythrocytes
Destruction (3 - 4 months)
Trapped in spleen and destroyed by
macrophages
Globin is recycled into amino acids
Iron is used to make new RBC’s
Rest of heme group converted to bilirubin
Bilirubin appears in urine and feces
Erythrocyte disorders
Athlete’s anemia
Thalassemia
Sickle-cell anemia
Blood doping among athletes
Leukocytes
The only complete cells
Protect against invasion
Move out of blood by diapedesis
Move through tissues by amoeboid motion
Follow chemical trails by chemotaxis
Leukocytes
Types
Granulocytes: contain cytoplasmic granules
Neutrophils, eosinophils basophils
Agranulocytes: without cytoplasmic granules
Lymphocytes, monocytes
Abundance: Never Let Monkeys Eat Bananas
Neutrophils
Characteristics
Multilobed (3 - 6 lobes) nucleus
Twice the size of RBC’s
Phagocytose bacteria
Eosinophils
Characteristics
Bilobed nucleus
Course granules stain deep red to crimson
Twice the size of RBC’s
Release digestive enzymes to kill worms (too large to
be phagocytosed)
Basophils
Characteristics
Course, dark purple, black granules
Twice the size of RBC’s
Release histamine (inflammatory chemical), attract
other WBC’s to the area
Lymphocytes
Characteristics
Large, dark purple nucleus
About the size of RBC’s
Act in immune response
Monocytes
Characteristics
Large, dark purple nucleus
Three times the size of RBC’s
Leave blood stream acting to phagocytose viruses and
bacteria
Platelets
Megakaryocytes (bone) rupture through
sinusoid capillaries
Enucleate, age quickly (10 days)
Hemostasis
Hemostasis
Phases
Vascular spasm
Platelet plug formation
Vasconstriction reduces blood flow
Platelets swell, and adhere to each other
Coagulation
Blood transformed from liquid to a gel
Hemostasis
Phases
Prothrombin activator
formed
Conversion into thrombin
Fibrin seals the hole
RBCs and fibrin mesh
Blood typing
RBC plasma membranes bear specific
glycoproteins recognized by the body
Glycoproteins called agglutinogens
ABO blood group (A, B, AB or O)
O (common), AB (least common)
Blood typing
Rh blood group
Rh factor: 8 Rh agglutinogens
C, D, E antigens most common
Carrying Rh symbolized by +
Blood groups reported together
(i.e., O+)
Rheology
The study of blood flow
Viscosity (i.e., polycythemia)
Rheology
Flow rate = 1/viscosity
Rheology
Flow rate is directly proportional to
differences in pressure
F ∞ P1 - P2 or (∆P)
Rheology
Flow rate is indirectly proportional to
vessel length (F = 1/L)
Rheology
Flow rate is directly proportional to the
fourth power of the radius of the vessel
F ∞ r4
Hemodynamics
Rate of blood flow highest in smallest cross
sectional areas
Functional significance
Total
area
Velocity
Blood flow
Laminar flow
Continuous (small vessels)
Pulsatile (large vessels)
Blood flow
Turbulent flow
Definition (obstruction, sharp turns, high flow rate)
Occurs after aortic and pulmonary valves or
valves in veins
Compliance
Tendency of blood vessel volume to
increase as pressure increases
C = ∆V/∆P
P1=160 mmHg, P2=120 mmHg, V1=5 l/min.
V2=3 l/min.
C = 0.05 kPa-1
Are veins or arteries more compliant ?
Compliance
8X more blood
3X more elasticity
24X more compliant