A&P - Chapter 29 (Part 2) Flashcards
What do capillaries connect?
Venules and arterioles
How many layers make up the capillaries?
1
What layer makes up the capillaries?
The tunica intima
- extremely thin
- flat epithelial cells
What do capillaries allow?
Substances to quickly pass through the wall
How do arteries distribute nutrients and gases throughout the body?
With movement of blood under high pressure
What assists in maintaining the arterial blood pressure? (2)
- Constricting
2. Dilating
What can veins/venules act as? Why?
- Reservoirs
2. Because they are low pressure vessels
What can veins do?
Expand to hold a larger amount of blood
What are the 4 types of circulation?
- Systemic circulation
- Pulmonary circulation
- Hepatic portal circulation
- Fetal circulation
What does the systemic circulation do?
Carries blood throughout the body
What does the pulmonary circulation do?
Carries blood to/from the lungs
What kind of blood is in the pulmonary arteries?
Deoxygenated
What kind of blood is in the pulmonary veins?
Oxygenated
What happens in the lungs during the pulmonary circulation?
Exchange of gases
- gets oxygenated
What does the hepatic circulation do?
It is a unique blood route through the liver
What blood from veins do not go directly into the IVC? (5)
- Spleen
- Stomach
- Pancreas
- Gallbladder
- Intestines
How does the blood get sent to the liver?
Through the hepatic portal vein
Where does blood go before re-entering the regular venous to the heart through the IVC?
Through the liver
- second capillary bed
Where are the 2 capillary beds?
- One is in the digestive organs
2. One is in the liver
What does the hepatic circulation assist with?
Homeostasis of blood glucose levels
- liver cells store
What function does the liver perform?
Detoxification
What does the fetal circulation refer to?
Circulation before birth
Why are modifications in the fetal circulation important?
Modifications required for fetus to efficiently secure oxygen and nutrients from material blood instead of its own lungs and organs which aren’t fully developed or functional
What are 6 unique structures of fetal circulation?
- Umbilical arteries
- umbilical cord - Placenta
- Umbilical vein
- umbilical cord - Ductus venosus
- Foramen ovale
- Ductus arteriosus
What do the umbilical arteries do?
They carry oxygen poor blood from the developing fetus to the placenta
How many umbilical arteries are there?
2
What does the placenta attach to?
The uterine wall
What does the placenta do?
It is the site of exchange of oxygen, nutrients, toxins and waste products between maternal and fetal blood
What umbilical vessel is the largest?
The umbilical vein
What does the umbilical vein do?
It carries oxygen rich blood from the placenta to the fetus
What do the 2-3 branches of the umbilical veins at the fetal liver become?
Continues as the ductus venosus
Ductus venosus
A continuation of the umbilical vein along the undersurface of the fetal liver
What does the ductus venosus shunt?
Most of the blood returning from the placenta to the fetus past the fetus immature liver into the IVC
