Circ Sys Flashcards
Function of the circ. system
1.Transportation of O2, CO2,wastes, nutrients, and hormones
2.Maintain body temperature
3.Maintain body fluid levels
Parts of the circ. system
The Heart: a muscular organ that continuously pumps blood through the body, generating blood flow. 2.The Blood Vessels: a system of hollow tubes through which the blood moves. 3.The Blood: The fluid that transports nutrients, O2, CO2and many other materials throughout the body.
Location of the heart
slightly behind and left to the sternum
Chambers of the heart
Atria- 2 top chambers that fill with blood returning from the body (RECEIVING)
Ventricles- 2 bottom chambers that receive blood from the atria and pump it out to the body/lungs (PUMPING)
BLOOD FLOW OUT
Vena Cava brings O2 poor blood to Right Atrium which flows to Ventricle which pumps the o2 poor blood to the lungs via pulmonary arteries
BLOOD FLOW IN
Pulmonary veins bring o2 rich blood back via left atrium, which flows to left ventricle, which pumps o2 rich blood through body via aorta
Purpose of valves
to prevent backward blood flow
LUB DUB SOUND
LUB-AV closing as blood is pumped from the atria to the ventricles
-“DUB” sound is caused by semilunar valves, as blood is pumped from the ventricles into the arteries
Vassa vasorum
vessels of vessels (small blood vessels that supply oxygen to the layers of the large blood vessels)
Nervi vasorum
nerve supply to large blood vessels, reg. via SNS
What are varicose veins?
enlarged veins caused by weak vein walls
What happens if circulation slows down
blood can clot in a deep vein leading to fatal pulmonary embolism if the clot goes to the lungs
Continuous vs fenestrated vs discontinuous/sinusoid capillaries
contin- least permeable (nerves, muscles, fat)
fenestrated- somewhat permeable (intestinal villi, endocrine glands, kidney glomeruli
sinusoid- very permeable (in liver, bone marrow, spleen; any large bodily exchange, such as protein or tissue)
Composition of blood
55%-plasma (fluid, 90% water), transports co2
45%-cells (solid), rbc-lose nucleus to carry more hemoglobin
1% of blood volume- wbc
leukocytes and lymphocytes
leukocytes (macrophages)- ingest foreign pathogens
- innate response, can pass via capillary walls
lymphocytes- recognize specific pathogens and fend them off if they attack again
- acquired response
what are platelets
non cell structures that help with blood clotting
fragments of large cells that break down in the bone marrow
Blood clotting process
Blood vessel Is broken=trigger
substances released attract platelets that release chemical agents called THROMBOPLASTIN
THROMBOPLASTIN reacts with PROTHOMBRIN to produce THROMBIN
THROMBIN reacts with FRIBRINOGEN to produce FIBRIN
FIBRIN- mesh strands and catches any escaping material to form a clot
Function of WBC and formation
locate the site of infection and other wbc to defend your body to produce antibodies for protection
They are formed in bone marrow, lymphocytes grow in thymus gland (T cells) and lymph node and spleen (B cells)
neutrophils
help protect your body from infections by killing bacteria, fungi, and foreign debris
lymphocyte
T cells, natural killer cells, and B cells to protect against viral infections and produce proteins
eosinophil
identify and destroy parasites, cancer cells and assist basophils with allergic responses
basophil
allergic response is producing; sneezing, coughing
monocytes
defend against infection by cleaning damaged cells
how many wbc are produced per day?
over 100 billion
What is stroke volume
volume of blood leaving the heart
What is heart rate
number of bpm (contractions)
blood pressure
120/80mmHg
systolic- highest pressure when heart beats and pushes blood around body
diastolic- heart relaxes btwn beats
what is cardiac output
amount of blood pumped from the heart per minute
= HR(SV), increased cardiac output, increased bp, increased hr
what is artierolar resistance
diameter of the Arteriole determines the amount of blood flow, increased diameter, means decreased bp
what is the diameter of blood vessels regulated by?
medulla oblongata
vasoconstriction
nerve impulses contract muscles, and vessels thin to reduce flow to tissues, increases pressure
vasodilation
nerve impulses expand/relax muscles, and vessels dilate to increase flow to tissues, decreases pressure
What is the SA node
sinoatrial node; stimulates the muscle cells to contract and relax rhythmically, also called a pacemaker (sets pace for cardiac activity), located in right atrium wall
the SA node generates and electrical signal forcing the two atria to contract together, and the signal reaches the AV node
What is the AV node
The AV node transmits the electrical signal through specialized fibres (purkinje fibres) that run down and around the septum and ventricles
initiates the simultaneous contraction of all cells including the right and left ventricles
