review of ABO/Rh compatibility

Artificial Pacemaker
uses electrical signals to prompt the heart to beat at a normal rate. Needed to treat arrhythmias. 

           heart rate =
​ heartbeats per minute

  Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps. 
It's measured in millimeters of mercury (mm Hg) and expressed as two numbers:
systolic = top number
 diastolic = bottom number

specialized structures that allow for synchronized contraction and cell to cell communication.  

there are anchoring sites that connect the actin filaments of the sarcomeres in one cell to the sarcomere in the neighboring cell so the contraction is synchronized among all muscle fibers.
they also have channel proteins that allow ions and small molecules to pass directly between adjacent cells which allows fast and synchronized movement of action potentials from cell to cell.

WBCs

kupffer cells line the sinusoids of the liver. they are phagocytes
that serve to breakdown "used" blood cells...

a blood pressure cuff works by temporarily compressing the brachial artery in your arm to measure blood pressure. The cuff is inflated to a pressure higher than your systolic pressure, temporarily stopping blood flow. As the cuff deflates, the device detects the return of blood flow, measuring systolic and diastolic pressures. 

Basophils
small and rare/ <1% of WBCs
release histamine (dilation) and heparin (< blood clotting)

The Fetal Heart

   Resistance:
       blood viscosity 
       vessel length
       vessel diameter
       turbulance 

 myocardial infarction = ​MI
heart attacks occur when a coronary vessel is blocked
 commonly by plaque formation called coronary thrombus.
Diagnosis by:
pain (not always/silent killers)
ECG/blood tests for cardiac enzymes released by damaged cells

blood pressure is a result of the heart pumping blood and the resistance it encounters along the way 

  pacemaker cells are modified cardiac muscle cells.

    Leucopoiesis

 circulatory system 

RBCs

  how are cardiac muscle cells different from skeletal and smooth muscle?

in lab we'll explore
blood flow through the heart

the pericardium has two main layers:
  1. fibrous pericardium is a tough, outer layer of connective tissue.
                It holds the heart in place.
  2. serous pericardium is the inner layer that's further divided into two sub-layers:
      a. parietal layer is attached to the inner surface of the fibrous pericardium.
      b. visceral layer (epicardium) directly covers the outer surface of the heart.

The pericardial cavity is the space between the two layers of the serous pericardium                which contains pericardial fluid. The fluid lubricates/reduces friction.

   The larger number is the pressure in the arteries as the heart pumps out blood during each beat. This is called the systolic blood pressure.
The lower number is the pressure as the heart relaxes before the next beat. This is called the diastolic blood pressure. Both are measured in units called millimetres of mercury (mmHg).​

systemic and pulmonary circulation  

  what's an autorhythmic cell?

arteries gradually change as they get farther away from the heart.

    heart rate is increased/decreased by changing the rate of depolarization in the pacemaker cells.

to decrease heart rate: ACh is released by parasympathetic neurons which alters K+ permeability of SA node cells. This delays the action potential slowing heart rate.
to increase heart rate: Sympathetic neurons release norepinephrine which opens the NA+/Ca+ channels increasing the rate of depolarization.

 capillary structure

             composed of endothilium 
   diameter : 8 micrometers (.008mm)                 (size of one red blood cell)

 inter-relationship
​ between systems

coronary artery disease = CAD
formation of atherosclerotic plaque reduces diameter of coronary artery/reducing blood flow=  coronary ischemia
reducing cardiac efficiency

 what's the pericardium?

pacemaker heart cells (cardiomyocytes) can generate electrical impulses (depolarize) without a stimulus. The initiate and regulate the heartbeat. pacemaker calls are primarily found in the sinoatrial (SA) node which is a crescent-shaped cluster of cells located in the upper wall of the right atrium. 
The electrical impulses generated by the SA node travel through the heart's conduction system which triggers the contraction of the heart muscle.

          stroke volume =
volume of blood pumped out of the left ventricle during one contraction

  low cardiac output
    indicates poor peripheral circulation

          vein types
large veins:
    ex: inf vena cava
    lumen diameter: 2cm

medium veins:
    ex: peripheral veins
    lumen diameter: 2-9mm
    
venules:
    ex: capillary bed
   lumen diameter: 20 micrometers

  depolarization - contraction - systole
  repolarization - relaxation - diastole

arteries have thicker, more elastic walls to withstand the high pressure of blood flow from the heart

  Eosinophils
few in number/approx 3% of WBCs
bilobed nucleus
engulf antibody identified pathogens
release cytotoxic chemicals via exocytosis (can kill large
     parasites)
increase in # with allergen presence
reduce inflammation

plasma proteins

  Blood Pressure

 pacemaker cells

will depolarize/initiate an
action potential all by themselves. their membrane potential "at rest" is approx. -60mV which is unstable.

this is called a pacemaker potential. pacemaker cells have membrane channel proteins called "funny channels" that have a weird permeability. These unique ion channels allow for spontaneous depolarization. 

pathology

    Lymphocyte
20-40% of WBCs
large round nucleus
exhibit three classes:
    t cells: cell mediated immunity
    b cells: antibody production
    natural killer cells: on patrol

    vascular phase > platelet phase > coagulation phase

 lymphatic system 

blood pressure
 arterial pressure rises during ventricular systole and falls during ventricular diastole.

Low O2 blood flows from fetus to placenta via umbilical arteries which arise from fetal internal iliac arteries.
HIgh O2 blood flows from placenta to fetus via single umbilical vein which drains into the ductus venosus, a shunt that allows blood in the umbilical vein to bypass the fetal liver.
The ductus venosus drains into the inf. vena cava. 

      cardiac output 

          veins

electrocardiogram = EKG/ECG

  what is a        capillary bed?

              venous valves
point in the direction of blood flow
prevent backflow 
if weakened, lead to varicoceles /hemorrhoids

  Neutrophils
most abundant (60%)
segmented nucleus w/2-5 lobes phagocytic first strikers         that destroy bacteria by fusing  engulfed cell with                 lysozome containing defensins
release hormones that increase permeability
      of vessels and attract other WBCs 
short shelf life (30 min to 10 hours)

White blood cells WBCs are also
called leucocytes.
1ml of blood exhibits 5ish x 10*6 RBCs and just 7500 WBCs.
​Most WBCs are found in the lymphatic tissue or connective tissue proper.  
WBCs that are in circulation are:

1. moved to the site of an infection/injury by + chemotaxis
2. sometimes capable of phagocytosis
3. capable of ameoboid movement
through endothelium into peripheral tissues via diapedesis.    

  intercalated discs

 whereas veins have thinner, less elastic walls and possess valves to prevent backflow  

                                                   Coagulation Phase
  extrinsic pathway: damaged endothelial cells begin the cascade   
  intrinsic pathway: activation of proenzymes in the blood begin the cascade

     Monocyte
2-8% of WBCs
large kidney bean shaped nucleus
become tissue macrophage after             24 hours in circ
release chemicals to attract other           WBCs

 Heart Arrhythmias:
abnormal patterns of a heart's electrical activity which
​may reduce efficiency of heart

Blood

After that first breathe, the foramen ovale closes due to a change in the relative pressure of both atria ensuring the separation of O2 rich and O2 poor blood. 

Sometimes, the closure is incomplete or will take a week to several months to close. About 20% of adults have an incomplete closure. 

Types of WBCs

               artery types:
elastic: closest to heart
              lumen diameter 1-2.5 cm
              ex: aorta
              high elastic rebound
muscular: most numerous
              lumen diameter 4mm (.4cm)                                  ex: brachial
             
arterioles:smallest of arteries
              lumen diameter 30 micrometers                                                 (.03mm or .003cm) 
              exhibit vasocontracition/vasodilation
​

    platelets
1.5-5 x 10*5/ml blood
shelf life approx 10 days
1/3 found in spleen where they are also
     degraded
thrombocytopoiesis occurs via
     megakaryocytes; 1 = 4000 platelets 

    Blood clotting