Lecture 12: Circulation Flashcards
What are vertebrate characteristics of the circulatory system?
- Blood cells contain hemoglobin
- Closed circulatory system
- Heart is compartmentalized into chambers
- Aorta positioned in front of spinal column, behind viscera
What are the tetrapod characteristics of the circulatory system?
- reduced number of aortic arches
- Pulmonary circulation (gills or lungs oxygenate blood)
What are the mammalian characteristics of the circulatory system?
- Pulmonary and systemic circuit chambers in heart completely isolated from each other
- Aortic arch on left
- Involvement in regulation of body temperature (homeotherms)
What is the one main characteristic specific to humans of the circulatory system?
-Increased efficiency in keeping brain cool
What is hemolymph, what type of organisms have this, ad what does it occupy?
Circulatory fluid of invertebrates, occupies homecoels
**different from hemoglobin because it uses hemocyanin and copper
What is an open circulatory system?
Blood is pumped into body cavities (hemocoels) where tissues are surrounded by blood (hemolymph)
What does the color of blood depend on?
The protein that is used to transport oxygen
How many chambers of the heart do fish have?
1 ventricle 1 atria
How many chambers of the heart do amphibians have?
2 atria, 1 ventricle
How many chambers of the heart do reptiles have?
2 atria 2 ventricle
How many chambers of the heart do mammals and birds have?
2 atria and 2 ventricles
The sequence of the ________ ________- ________-_________-__________ _______ in the primitive heart is mirrored in living fishes an din the early-stage human embryonic heart
Sinus venosus-atrium-ventricle-conus arteriosus
What is the sinus venosus?
Confluence of major veins (bringing blood to heart)
What is the conus arteriosus?
Strongest contraction; pumps blood out to vessels
There transition from the primitive four chambered heart to the modern mammalian is an excellent example of how evolution can work within what?
The framework of ontogenetic sequences to changes a developmental process by extending it in a new direction
What is “ontogeny recapitulating phylogeny”?
During their development, organisms repeat evolutionary stages of ancestral species
**this doesnt actually occur
The observation that many even distantly related species resemble each other at early developmental stages reflects how changes in developmental timing (__________), and/or the retention of juvenile characteristics in some species (________) are ways in which evolution works within already existing complex systems.
Heterochrony
Neoteny
How doe the atrioventricular valves function?
OPEN:
1. Blood returning to the heart fills atria, putting pressure against AV valves; forced open
2. As ventricles fill, AV valve flaps hang limply into ventricles
3. Atria contract, forcing additional blood into ventricles
CLOSE:
1. Ventricles contract forcing blood against AV valve cusps
2. AV valves close
3. Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria
How do the Aortic and semi-lunar valves function?
- As ventricle contract and intraventricular pressure rises, blood is pushes up against semilunar valves, forcing them open.
- As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close
Which arteries make up the branches of left coronary artery and what is another name for these?
- Circumflex artery
- Anterior interventricular artery
**A.k.a. Left anterior descending (LAD)
Where do the coronary arteries come off of?
The ascending aorta
What does the pulmonary circuit consist of?
The chambers on the right side of the heart (R Atrium and ventricle) as well as the pulmonary arteries and veins
What does the systemic circuit consist of?
Chambers on the left side of the heart (L atrium and ventricle), along with all the other named blood vessels
Blood pumped out of the R ventricle is pumped into what?
Pulmonary artery to the lungs
The pulmonary trunk bifurcates into what two things?
L pulmonary artery and R pulmonary artery
What are the 2 branches of the R coronary artery?
Posterior interventricular artery
R marginal artery
Mammalian fetal circulation reflects the reliance of the developing fetus on what?
Maternal blood supply
Are fetal lungs functional? How do they develop?
Not functional, no pulmonary circuit yet but enough blood to allow lungs to develop
Where does oxygenated blood from the placenta pass through in the fetus?
From placenta through liver, enter the IVC, flows into the R atrium of heart
Are the atria fully separated in the fetus?
No, some blood form the IVC flows through the foramen oval into the R atrium
Where does blood from the SVC in the fetus flow into? Why?
The R ventricle this functions to reduce volume and pressure of blood pumped into the R ventricle
What allows more blood to be diverted away from the lungs and into the aorta and out to the fetal body?
Ductus arteriosus between the aorta and the pulmonary trunk
In the fetus, where is the most highly oxygenated blood diverted to?
The developing heart tissue and itself and the brain