The Circulatory System Flashcards
Function of the circulatory system
- Circulate blood to body
- Transport O2, water and nutrients to cells in the blood
- Transport CO2, and wastes away from the cells
- Maintain body temperature
- White blood cells fight infection
Vasodilate / vasoconstrict
Arteries open up ( vasodilate ) and constrict ( vasoconstrict) to allow more or less blood to reach certain areas of the body
Systemic circulation
Carries blood from the heart to all parts of the body (except lungs) and back again
Left side of heart pumps oxygenated blood to rest of body via aorta
Pulmonary circulation
Carries blood from heart to lungs and back again
Arteries function
Carries blood away from the heart
Blood is pushed through the arteries caused by contractions of the heart
Flow or surge of blood through the arteries with each heart beat can be felt near the surface of the skin - this is referred to as the pulse
Arteries structure
- oxygenated
- Increasing high blood pressure
- no valves
- thick, muscular
Veins function
Carry blood towards the heart
Valves which allow the return of blood to the heart, but prevent the back flow of blood
Veins structure
- Thick valves
- low blood pressure
Capillaries - function
Tiny blood vessels which reach every cell of the body
Allow the passing of oxygen to tissues and removal of carbon dioxide
Functions of blood
- Transport of nutrients and waste products
- Regulation of body’s temperature
- Protection of the body
→ white blood cells
Plasma (55%)
Clear yellow fluid, 90% is water
Plasma carries blood cells
Provides cells with antibodies, proteins, glucose, salts, fats
Red blood cells (RBC’S) (45%)
Responsible for carrying O2 to cells & removal of CO2
→ from cells of muscles and organs
White blood cells ( WBC’s) (<1%)
Responsible for moving to sites of infection where they destroy bacteria & other disease causing organisms
Platelets (very small percentage)
Produced in bone marrow-cause blood clot when vessel damaged - prevent excess bleeding
Functions of the respiratory system
- Deliver oxygen front the atmosphere to the lungs
- Provide method of gaseous exchange within the lungs
- Creates speech
- Facilitate sense of smell
- Expels heat
Structure of the respiratory system
- Air passages
- Lungs
- Diaphragm
Air passages
Nasal cavity
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
Diffusion
The movement of substances from a high to low concentration through a semi-permeable membrane
Alveoli features that allow efficient gas exchange to occur
Large surface area to volume ratio - so lots of opportunity for gas exchange to occur
Surrounded by capillaries - to occur exchange to occur efficiently into the blood
Very thin walls - to promote diffusion of gases
Structure of the circulatory system
Heart
Arteries
Veins
Capillaries
Blood
The diaphragm
Involuntary or smooth muscle
contracts and relaxes
aids breathing - all time
Moves up and down
Inspiration
Volume of lungs increases
External intercostal muscles contract
internal intercostal muscles relax - lift rib cage up and out (cause larger volume - area of low pressure)
Diaphragm contracts - flatten
Air enters lungs from high to low pressure
Expiration (breathing out)
Volume of lung decreases
External intercostal muscles relax
internal intercostals contract to lower rib cage
diaphragm relaxes - dome shape (smaller volume and this area of high pressure)
Air exits lungs from area of high pressure to low
Capillaries - structure
Very thin walls - only 1 cell thick
Branch from the arterioles and venule to form a network
Process of oxygen from atmosphere to all around the body and back to the heart
Atmosphere
Nasal cavity
Oral cavity
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
Capillaries
Pulmonary veins
left atrium
Left ventricle
Aorta
- around body through arteries
From muscles through veins
Superior/inferior vena cava
Right atrium
Right ventricle
Pulmonary artery
To lungs
Oxygenated/deoxygenated
Left atrium and ventricle - oxygenated
Right atrium and ventricle - deoxygenated
Voice box
Larynx
