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Homeostasis
relative consistency of the internal environment
changes do occur, but they are small and kept within narrow limits
without it we die
circulatory, respiratory and digestive systems work together to maintain ____________
Internal Environment
extracellular fluid (i.e., the fluid that surrounds each cell)
Homeostatic Control System
a collection of body systems that function to maintain homeostasis
Circulatory System
transport blood throughout the body’s tissues
Respiratory System
exchange of carbon dioxide and oxygen
Digestive System
Digestion and absorption of organic nutrients, salts, and water
Three main delivery parts of the Circulatory System
A pump (heart)
Plumbing (blood vessels)
Fluid (blood)
Function of the Heart
to force the blood to all parts of the body
Function of Blood Vessels
to carry or hold the blood throughout its entire journey (to muscles, lungs etc.)
Major Types of Vessels
Arteries
Veins
Arterioles and Venules
Capillaries
Arteries
large blood vessels that carry oxygenated blood AWAY from the heart
must withstand pressure of blood forced through them
elasticity allows them to expand and snap back as blood passes through, this keeps blood flow in right direction, and provides additional pumping motion to help force blood through.
Veins
large blood vessels that carry deoxygenated blood TOWARD the heart
thinner walls and larger diameter compared to arteries to readily receive blood
work against gravity and rely on valves to maintain blood flow in one direction
Capillaries
extremely small blood vessels that are located within tissues; gas exchange between cells occurs here
link between arteriole and venous system
very narrow —> forces RBCs to travel through single fine (1 cell at a time)
Function of blood
to carry nutrients and oxygen most of the time; dissolved in plasma, red blood cells
8% of body weight (70kg)
5.5L = blood volume
resting cardiac output = 5L/min
circulation time = 1 min
2 types of Cardiac Circulation
Pulmonary Circulation
Systemic Circulation
Pulmonary Circulation
Pathway of blood from the heart to the lungs and back
Systemic Circulation
Route from the heart to the rest of the body
Aorta
Largest artery in the body
Three layers of Arteries
Inner Layer: Epithelial cells (one cell thick) - reduces friction allowing blood to move through smoothly
Middle Layer: smooth muscle and elastic fibers
Outer Layer: connective tissue with elastic fibres
Arterioles
Similar to arteries, smaller in diameter and carry oxygenated blood from arteries to capillaries
Purpose of thin membrane and slower pace in Capillaries
allows capillaries to exchange oxygen and carbon dioxide through diffusion
Passive Transport Diffusion
Movement of molecules from a region of high concentration to low concentration
Difference in concentrations between regions is called concentration gradient
Works well over short distances
Venules
smaller than veins, merge from capillaries to dorm veins carry deoxygenated blood
Purpose of skeletal muscles in circulatory system
contractions help push blood through removing some pressure from veins
Varicose Veins
caused by standing or sitting for a long time as it prevents skeletal muscles from squeezing blood back to heart
valves over worked resulting in blood flowing back over time
veins constantly being stretched as blood pools in them and bulge
Blood
the body’s main extra-cellular fluid
Average human has 4-6L
If blood was put into a centrifuge, it separates into…
Plasma and Formed Elements
Plasma
accounts for 55% of blood volume
Water
90% of blood
10% of blood
blood proteins, salts, hormones, glucose, vitamins, minerals, dissolved gasses and waste products
What proteins does plasma dissolve
Albumins
Globulins
Fibrinogens
Albumins
along with minerals, they play an important role in establishing osmotic pressure that draws water back into capillaries
Globulins
Produce antibodies that provide protection against invading microbes
Fibrinogens
important in blood clotting
Formed Elements
Make up 45% of blood volume
“buffy coat”
Leucocytes (white blood cells)
Platelets (cell fragments) - 1%
Erythrocytes (red blood cells) - 99%
Leukocytes (WBCs)
0.9% of Buffy Coat
Produced in bone marrow and lymph glands
Immune defense and cleanup functions
Move by amoeboid movement (searches for bacteria/disease filled cells and WBC will surround it and engulf it (phagocytosis)
pus sometimes forms at the site
Pus from WBC at the site of cuts or scrapes
combo of living and dead WBCs and bacteria
Phagocytosis
used by WBC to engulf bacteria
Typed of Leukocytes
Granulocytes - grainy appearance
Neutrophils
Eosinophils
Basophils
Agranulocytes - smooth appearance
Lymphocytes'
Monocytes
Phagocyte
general term given to any leukocyte that engulfs bacteria
Neutrophils
most abundant leukocytes found in body tissues and blood (help to engulf bacteria)
Eosinophils
found in mucous lining of digestive and respiratory tract
Basophils
aid in immunity by secreting substances that attract phagocytes to destroy pathogens
Lymphocytes
help to remember past foreign invaders and help to destroy them
Monocytes
circulate in blood stream for a few days then become bacteria destroying macrophages
Platelets (buffy coat)
0.1%
AKA thrombocytes
from megakaryocytes in bone marrow
Membrane bound fragments of cells that break apart from larger cells in bone marrow
Lifespan is 7-10 days
key role in blood clotting
Step 1 and 2 of Platelets and Blood Clotting
Platelets encounter damaged blood vessels (rough surface) and break open
Release ‘clotting factors’ – help platelets stick together to form a plug
Clotting factor – thromboplastin
Step 3 of Platelets and Blood Clotting
Thromboplastin reacts with calcium and activates plasma protein prothrombin changing it to thrombin
Step 4 of Platelets and blood clotting
Thrombin converts the plasma protein fibrinogen into fibrin threads
Fibrin forms a scaffold to help repair process begin
Many fibrin strands gather at the ends of the vessel to form a mesh clot
Clots trap blood cells and prevent them from passing through a damaged blood vessel
Scab
fibrin, platelets, blood cells mesh together to seal a wound until new tissues can grow and repair the broken skin
RBCS (formed elements)
formed in the liver (fetus) and bone marrow (post birth)
no nucleus (enucleated) to keep them health
lifespan of 120 days
main function to carry oxygen
How Oxygen binds to an RBC
RBC contain hemoglobin molecules which contain 4 atoms, that each bond to an oxygen
each RBC bonds to 4 oxygen atoms
about 280 million hemoglobin molecules in a single RBC
Function of Cell Membrane
Transport oxygen into and out of the cell
Transport carbon dioxide into and out of the cell
Cause of Gas Exchange
oxygen pick-up and release factors
concentration of oxygen
acidity of surrounding fluid
Increased Acidity and Gas exchange
will loosen bonds between heme group and oxygen which result in released oxygen
acidity influenced by presence of dissolved carbon dioxide
Cardiac Output
the efficiency of the heart, the volume of blood pumped by each ventricle per min
usually L/min
Equal amount of blood pumped
on the right and left side of the heart
2 factors that affect Cardiac Output
stroke volume
heart rate
Stroke Volume
quantity of blood ejected by each ventricle during each contraction
the stronger the heart contractions, the greater the store volume
Blood in ventricles
not completely emptied, thus stronger contractions can eject more blood
Amount of blood leaving each ventricle while you are resting
70mL
types of Contractions AKA Systole
Cardiac Diastole
Atrial Systole
Ventricular Systole
Heart Rate
number of times the heart beats per minute
average = 72bpm
Calculation for Cardiac Output (CO)
Heart Rate x Stroke Volume
Cardiac Output and body mass
the greater the mass, the greater the cardiac output needed to supply blood to all the cells
Cardiac Output and energy
the more energy body needs (ex. while exercising) the greater the cardiac output must be
Heart rate during exercise
150-180bpm
How fitness impacts stroke volume and heart rate
people in better shape have a strong heat so then is an increases strong volume and as a result heart rate is lowered
Heart
muscular organ that functions as a pump
able to contract to force blood out of heart
has chambers that receive and deliver blood, has valves to direct blood flow
Tissues of the Heart
Endocardium
Myocardium
Endocardium
smooth tissues that lines the inside of the heart
speeds up blood flow as it prevents anything from sticking and allows blood to flow smoothly
Myocardium
muscle tissues that allows heart to contract and contains own pacemaker and nervous tissues that responds to stimuli to control the heart
Smaller Blood Receiving Chambers
Left & Right Atrium
Larger Blood Delivery Chambers
Left & Right Ventricles
Pulmonary circulation
part of the circulatory system that carries deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart. It involves the pulmonary arteries, capillaries in the lungs, and pulmonary veins.
Valves of the Heart
prevent backflow of blood as it leavers the previous valve
Atrioventricular Valves and Semi-Lunar Valves
Atrioventricular Valves
separates atria and ventricle
Tricuspid
Bicuspid/Mitral
Tricuspid Valve
separates right atrium and right ventricle
has 3 flaps
Bicuspid/Mitral Valve
separates left atrium and left ventricles
Semi-Lunar Valves
semi-moon shapes
Aortic valve
Pulmonary valve
Aortic semi-lunar valve
separates left ventricle and aorta
Pulmonary semi-lunar valve
separates right ventricle and pulmonary artery
Atrial Septal Defect
a hole in the heart
type of congenital heart defect in which there is an abnormal opening in the dividing wall between the upper filling chambers of the heart (the atria)
What causes your heart to beat
Sinoatrial node (pace maker)
Sinoatrial node
located in the right atrium and maintains in ternal pumping rhythm by causing muscle to contract and pump out the blood. Stimulates atria first, impulse then is conducted to the ventricles through a form of the junction box
Junction Box
called the atrioventricular (AV) node
Artificial Pacemaker
Electronic device inserted under skin to help heart beat regularly and at an appropriate rate. Has leads that travel through a large vein to the heart which send electric impulses to the heart to tell it to beat.
The heart cycle
consists of 2 phases of relaxation (diastole) and contraction (systole)
Diastole
diastolic pressure when blood pressure is reduced since heart is relaxed. Valves open to allow blood to flow into ventricles. Blood flows into all 4 chambers
Systole
blood is forced from heart so ventricles contract . Blood travels through pulmonary trunk and aorta. Systolic pressure since blood pressure increases (goes faster as pushed)
Heart sounds from systole
tricuspid and bicuspid valves close to prevent blood flowing back to atria (lub sound).
Aortic and pulmonary semi-lunar close (dub).
Average Systolic:Diastolic
120mmHg : 80 mmHg
RBC diffusion with lungs
RBC enter lungs with low concentration, oxygen from lungs (high concentration) diffuses into RBC’s
RBC diffusion with muscles
Muscles have low oxygen concentration so oxygen diffused from RBC (high concentration) to muscles
Oxygen concentration and gas exchange
weakens bonds between heme group and oxygen, causes release of oxygen
Gas Exchange and cellular respiration
Alot of carbon dioxide is released from tissue, so higher acid, so more oxygen released from RBC into tissue. OR alot of oxygen is used by tissues, so low concentration of oxygen, weakens bonds in RBC and more oxygen is released from RBC. Oxygen carred by the blood is released at the same rate as the cells’ rate of respiration
Erythropoiesis
regeneration of RBC’s, erythropoietin hormone involved
Function of Blood - Transport
minteral and nutrients (from digestive system), hormones (from endocrine system), gases (from respiratory system), waste products (from cellular processes amino groups from de-amination of amino acids from protein)
Vasodilation
Function of blood - temperature regulation. Blood vessels widen to increase blood flow near body surface, helps promote heat dissipation if core body temp is too high