Chapter 44: Circulatory System Flashcards
What is the circulatory system consist of?
heart, vessels, and fluid (blood) moving important molecules and cells from one tissue to anther
What is the lymphatic system?
accessory system of vessels and organs that helps balance the fluid content of the blood and surrounding tissues and participates in the body’s defenses against invading disease organisms
ISF and always removing
What type of animals can rely primarily on diffusion? ex?
very small or thin animals, ex) sponges, cnidarians, flatworms
What is fluid?
a specialized medium carries cells, O2, nutrients, CO2 and wastes, and plays a major role in homeostasis
ex) blood
What is the role of the heart?
the muscle that pumps fluid through the circulatory system
What are vessels?
tubular vessels distribute the fluid pumped by the heart
What type of circulatory system do sponges have?
water is pumped in through pores in the body wall and exits through a large, central cavity
What type of circulatory system do cnidarians have?
have a central gastrovascular cavity with a mouth through which water enters and leaves
Describe an open circulatory system?
vessels leaving the heart release bloodlike fluid
(hemolymph) directly into body spaces (sinuses) that surround organs – hemolymph reenters the heart through valves in the heart wall
blood and ISF combined
has valves to create directionality and stop back flow
Describe and closed circulatory system?
the fluid (blood) is confined to blood vessels and is distinct from the interstitial fluid –substances are exchanged between blood and interstitial fluid, then between interstitial fluid and cells
capillary beds
What is the design of the circulatory systems for invertebrates?
open circulatory systems with one or more muscular hearts
The more active insects and crustaceans have specialized air passages (tracheae) that aid in gas exchange
What organisms have closed circulatory systems?
Annelids (earthworms) , cephalopod mollusks, and all vertebrates
What part of the heart receives blood returning from the heart?
atria
What part of the heart pumps blood from the heart?
ventricles
Heart design of sharks and bony fishes?
one atrium and one ventricle
The ventricle pumps blood to capillaries of the gills, where blood releases CO2 and picks up O2
Oxygenated blood is delivered to capillary networks in other body tissues, where it delivers O2 and picks up CO2
Deoxygenated blood returns to the atrium in veins
Heart design of turtles, lizards, and snakes?
2 atria and 1 ventricle
A flap of tissue in the ventricle (incomplete septum) keeps oxygenated and deoxygenated blood almost completely separate
The systemic circuit carries oxygenated blood to body tissues
The pulmonary circuit carries deoxygenated blood to the lungs
Heart design of Crocodilians, birds, and mammals?
double heart consisting of two atria and two ventricles
—4 chambers
complete septum
How much blood does the average adult human have?
4-5 L
What percentage does plasma make up in the blood?
55-58%
What is hematocrit?
the remaining solid (cellular) components
Where do blood cells develop in humans?
develop in red bone marrow – primarily in the vertebrae, sternum, ribs, and pelvis
come from pluripotent stem cells
What do pluripotent stem cells differentiate into?
myeloid and lymphoid stem cells
What can myeloid stem cells become?
platelets, erythrocyte, basophil, eosinophil, neutrophil, monocyte/macrophage
What can lymphoid stem cells become?
B lymphocyte and T lymphocyte
What cells are in the bone marrow?
pluripotent stem cell, myeloid and lymphoid stem cells
Function of blood?
transports cells and molecules
stabilizes pH and salt composition of body fluids
regulates body temperature by transferring heat
What is blood plasma made of? (10)
mainly water (91-92%) glucose and other sugars amino acids plasma proteins dissolved gasses (O2, CO2, N2) Ions (Na, K, Ca, Cl, HCO3) lipids vitamins hormones metabolic wastes (urea and uric acid)
What are 3 examples of plasma proteins? where do they made?
albumins, globulins, fibrinogen
made in liver
What are albumins?
important for osmotic balance and pH buffering
What are globulins?
transport lipids and fat-soluble vitamins
What are fibrinogens?
used in blood clotting
Erythrocyte lifespan? nucleus?
120 days, mammal erythrocytes lose their nucleus
What is hemoglobin?
Hemoglobin, which gives erythrocytes their red color, has four polypeptides, each linked to a heme group that contains a central iron atom The iron atom binds O2 molecules in the lungs and releases O2 in other body tissues
How does carbon monoxide affect hemoglobin?
blocks and won’t hemoglobin’s ability to combine with O2 let go and can quickly lead to death
How many erythrocytes are produced in the average human each second?
2-3 million
What and where are erythrocytes destroyed by?
by macrophages in the spleen, liver, and bone marrow
What is erythropoietin? (EPO)
stimulates stem cells in bone marrow to increase erythrocyte production
What can anemia be caused by? problem it creates?
can also be produced by blood loss from a wound, by certain infections, lack of iron, or by dietary insufficiencies
too few or malfunctioning erythrocytes, which prevent O2 from reaching body tissues in sufficient amounts
Do leukocytes retain their nuclei? ribosomes?
yes and yes
What do platelets contain?
enzymes and other factors for blood clotting
What is thrombin?
what platelets release that travels in the blood. It converts fibrinogen in to fibrin (sticky) to form a blood clot
What are atrioventricular (AV) valves?
between atria and ventricles
What are seminlunar (SL) valves?
between ventricles and arteries leaving the heart (aorta and pulmonary arteries
What are the 2 circuits?
pulmonary and systemic
Which organ is the first to receive oxygenated blood?
heart
How does the heart receive its blood supply?
via coronary circulation
The aorta gives off two coronary arteries that branch extensively, leading to dense capillary beds that serve the cardiac muscle cells
The blood from the capillary networks collects into veins that empty into the right atrium
What happens in systole?
ventricular contraction and emptying
What happens in diastole?
relaxation and filling between contractions
What makes up 1 heartbeat?
1 systole and 1 diastole
What makes up the lub-dub sound?
first sound is the AV valves, the second is the SL valves
sounds come from closing of valves from ventricles
What are heart murmurs?
are abnormal sounds produced by turbulence in blood when one or more valves fails to open or close completely and blood flows backward
What type of pressure occurs in the blood vessels?
hydrostatic pressure
What is the difference between neurogenic and myogenic hearts?
the nervous system controls the heart beats in neurogenic hearts
myogenic hearts can produce heart beats by themselves
What animals have neurogenic hearts? myogenic hearts?
some crustaceans
myogenic: insects and vertebrates
What does the sinoatrial node (SA node) do?
coordinates contractions of individual cardiac muscle cells, made of pacemaker cells
What are pacemaker cells? types of channels used for depolarization?
specialized cells in the upper wall of the right atrium
ion/leak channels
Does the vena cava have valves?
nope
What does the atrioventricular node (AV node) do? location?
Cells of the AV node are excited by the atrial wave of contraction, generating a signal that travels to the bottom of the heart via Purkinje fibers
A short delay in transmission from AV node to ventricles allows atria to finish contraction before ventricles contract
located in the heart wall between the right atrium and right ventricle
know eeg
okay
What are the three layers of the artery walls?
An outer layer of connective tissue containing collagen and elastin fibers, which gives the vessel recoil ability
A relatively thick middle layer of vascular smooth muscle cells, also mixed with elastin fibers
A thin inner layer of flattened cells (endothelium)
What is the structure of a capillary wall?
Capillary walls consist of a single layer of endothelial cells through which gases, nutrients, and wastes are exchanged with the interstitial fluid
What is a precapillary sphincter?
A small ring of smooth muscle at the junction between an arteriole and a capillary adjusts the rate of flow through the capillary networks
If the resistance to blood flow in capillaries high or low? what does this cause?
high, so blood slows down allowing maximum time for exchange of substances between blood and tissues
What can freely move between blood and ISF?
water, ions, small molecules (glucose), leukocytes
What cannot freely move between blood and ISF?
erythrocytes, platelets, and plasma proteins
What are the 2 major mechanisms drive exchange of molecules and ions between capillaries and interstitial fluid?
(1) diffusion along concentration gradients
(2) bulk flow
Where is diffusion greatest?
Total diffusion is greatest near the arterioles, where the concentration differences between blood plasma and interstitial fluid are highest
How does bulk flow work? highest?
Bulk flow carries water, ions, and molecules out of the capillaries through spaces between capillary endothelial cells
driven by blood pressure, which is higher than the pressure of the interstitial fluid
greatest near the arterioles, where the pressure difference is highest
What happens to the valves in the veins when muscles contract?
valves open and blood returns to heart
What can a lack of skeletal muscle activity can lead to?
blood clots (deep vein thrombosis)
What is the difference between an ischemic stroke and hemorrhagic stroke?
ischemic stroke is an area deprived of blood and hemorrhagic stroke is an area of bleeding in the brain
What are the 3 main mechanisms for regulating blood pressure?
- controlling cardiac output,
- degree of constriction of blood vessels (primarily arterioles),
- total blood volume
What are baroreceptors? pathways used?
Baroreceptors in the cardiac muscle, aorta, and carotid arteries
constantly provide information about blood pressure
Signals from baroreceptors go to the medulla in the brain stem – the brain stem sends signals via the autonomic nervous system that adjust the rate and force of the heartbeat
What can vasodilation be caused by?
low O2 and CO2 (exercising), NO
Purpose of lymphatic system?
collects excess interstitial fluid (lymph) and returns it to the venous blood
also collects fats that have been absorbed from the small intestine and delivers them to the blood circulation
key part of immune system
What tissues and organs make up the lymphatic system?
lymph nodes, spleen, thymus, and tonsils
How does the lymphatic system work in the immune system?
These filter viruses, bacteria, damaged cells, and cellular debris from the lymph and bloodstream, and help defend the body against infection and cancer
What do lymph nodes contain?
macrophages and leukocytes
What do lymphatic vessels allow in?
everything
Pathway for lymphatic vessel? how can you help this movement?
Lymph vessels lead to the thoracic duct and the right lymphatic duct, which empty the lymph into a vein beneath the clavicles (collarbones)
Movements of skeletal muscles and breathing movements help move the lymph through the vessels
