cardiovascular system Flashcards
When does vasculature develop?
Begins at 3-4 weeks after conception
Vasculogenesis vs Angiogenesis
Vasculo- formation of arteries and veins, mesodermal cells differentiate into vessels during embryonic development
Angio- formation of vascular branches from existing blood vessels, occurs during embryonic development and through life
What are the 3 layers of blood vessels?
Tunica externa, tunica media, tunica intima
Two important arteries in tunica media?
Large elastic arteries and medium muscular arteries
What are the 3 classes of veins?
Large veins, medium/small veins, and venules
When does the heart develop during embryonic phase?
Heart develops approx 3 weeks after conception
When dies circulation begin in embryos? When dies heart become 4 chambers?
4 weeks circulation
7 weeks 4 chambers
What are shunting systems?
Small passages for blood to travel through the body to bypass undeveloped foramen
1) foramen ovals- r atrium to left atrium
2) dictums arteriosus- r pulmonary artery to aorta
3) ductus venosus- inferior vena cava to umbilical vein
How many births have congenital heart disease?
1 percent of live births have congenital heart disease
Which side becomes more dominant during adulthood?
Left ventricular wall becomes twice as thick by adulthood
Heart volume at birth, 6 months , 2 yrs old?
40 mL at birth
80 mL at 6 months
2 age- 160 mL
ratio remain constant - 10 mLKg
Vascular changes in infancy?
At birth- 1 vessel for every 6 muscle fibers
Adulthood- 1:1 ratio
Heart changes with aging?
- decrease in number of myocytes, but increase in size
- decrease in number of pacemaker cells in SA node- slower HR
- Left ventricular wall becomes thicker- decrease stroke volume
- Myocardium becomes darker
- Thickening and calfication of valves
Hb levels fetus vs post natal?
70% in umbilical vein, 97% in arterial blood after birth
Vessels and blood changes with aging?
Vessels: become thicker, stiffer, and less flexible
Blood: decreased blood volume, decreased number of red blood cells, impaired ability to fight infection because less lymphocytes
What are the 2 zones of the pulmonary system?
Conducting Zone- where air is moved in and out
ex. nose, pharynx, larynx, trachea
Respiratory Zone- where air exchange occurs
ex. alveoli, alveolar ducts
Where is the respiratory system located in the brain?
Medulla oblongata and pons
Sympathetic vs Parasympathetic response for Respiration?
Sympathetic: Bronchiole Dilation
Parasympathetic: Bronchiole Constriction
Tidal volume, residual volume, and minute ventilation?
Tidal volume- amount of air inhaled or exhaled with each breath
Residual volume- amount of air remaining in the lungs following expiration
Minute ventilation- total volume of air inspires and expired in one minute
Pulmonary development at 4-8 weeks of gestation?
- Differentiation of trachea and bronchi
- Lung buds form
- Bronchi begin to form in the lungs
In what week is surfactant produced?
24 weeks
Pulmonary development at birth?
At birth, rib cage is horizontal and ventilatory muscles are not developed
Ribs become angles and more efficient breathing once able to sit
Pulmonary development in infancy and childhood?
- increase number of alveoli until age 8 years old
- airways are smaller for children, decreased smooth muscle in bronchiole walls until age 3-4 yrs old
- increased risk of respiratory infections until 6-8 years old
Pulmonary development in adolescence?
at 19 years old, smooth muscle in arterial walls of alveoli are filly developed
Pulmonary development in adulthood and aging?
Functional impairments evident beginning in the 7th decade of life
Altered length tension relationship of muscles due to structural changes in thoracic cavity
—> leads to increased work of breathing
