UNIT 3 – PART 1
CIRCULATORY & EXCRETORY SYSTEMS
1
THE CIRCULATORY SYSTEM
2
FUNCTIONS
• To transport O2 to the cells of
the body so that cells may do
cellular respiration
• To Transport nutrients to the
cells of the body
• To transport CO2 and cellular
wastes away from the cells
3
PARTS
• Heart
• Blood Vessels
• Blood
4
COMPONENTS OF BLOOD
• Red blood cells
• White blood cells
• Platelets
• Plasma
5
WHAT ARE RED BLOOD CELLS?
• Also called erythrocytes
• Transport oxygen
• Shaped like disks
• Produced in the red bone marrow
• Contain Hemoglobin
• An iron containing protein that
binds to oxygen
• Gives blood a red color
6
WHAT ARE WHITE BLOOD CELLS?
• Also called leukocytes
• Produced in the red bone marrow
• Can live for days, months or even
years
• Guard against infection, fight
parasites, and attack bacteria
• Can leave the circulatory system
and go into the immune system
fighting infection
7
WHAT ARE TWO KINDS OF WHITE
BLOOD CELLS?
• Phagocytes (eating cells)
• Engulf and digest disease causing bacteria
• Lymphocytes
• Produce antibodies that are proteins to help
destroy pathogens
8
WHAT ARE PLATELETS?
• Cell fragments needed for clotting
• Made in bone marrow
• Clotting process
• Platelet comes in contact with edges
of broken blood vessel and becomes
sticky
• A cluster of platelets gathers around
the wound forming a clot (scab)
9
WHAT IS PLASMA?
• Fluid part of blood (mostly made of
water)
• Straw colored
• Transport fatty acids, hormones and
vitamins
• Regulate osmotic pressure and blood
volume
• Fight viral and bacterial infections
• Aid in blood clotting
10
TYPES OF BLOOD VESSELS
• Arteries
• Large and thick-walled
• Carry blood from the heart to the
rest of the body
11
TYPES OF BLOOD VESSELS
• Veins
• Smaller than arteries and not as thickwalled
• Carry blood from the rest of the body
back to the heart
12
TYPES OF BLOOD VESSELS
• Capillaries
• Tiny blood vessels with walls that are only
one cell thick
• Oxygen and nutrient absorption take place
in the capillaries
• Also move CO2 and waste products into the
blood from cells
13
THE HEART
14
BLOOD FLOW THROUGH THE HEART
• Oxygen poor1.) Superior and
inferior vena cava
2.) Right Atrium
• Oxygen rich5.) Left Atrium
6.) Left Ventricle
3.) Right Ventricle
7.) Aorta
4.) Lungs
8.) Body
15
BLOOD FLOW THROUGH THE BODY
• Pulmonary circulation
• Right side of the heart pumps blood from
the heart to the lungs
• Systemic circulation
• Left side of the heart receives blood from
the lungs and pumps it to the rest of the
body
16
CLOSED VS. OPEN CIRCULATION
• Closed circulation – blood is
contained in a system of vessels
and forced through them by a
heart or heart-like organ
• Open circulation – blood is
partially contained in a system of
vessels; a heart or heart-like
pump pushes the blood though
spongy tissues
17
18
THE EXCRETORY SYSTEM
FUNCTION OF THE EXCRETORY
SYSTEM
• Maintains homeostasis in
the body by removing waste
products from the cells and
expelling them from the
body
• Single-celled organisms can
use active transport or
diffusion
• Multicellular organisms
must have a complete
system
PARTS OF THE EXCRETORY SYSTEM
• Kidneys :
1. remove waste products from the blood
2. maintain blood pH
3. regulates total blood volume by controlling water
content in blood
• Ureters
• Urinary Bladder
• Urethra
• Skin – releases excess salts and water through pores
• Lungs – remove excess carbon dioxide from the blood
PARTS OF THE EXCRETORY SYSTEM
KIDNEY STRUCTURE
• 2 regions of kidney
• Renal cortex-outer
region
• Renal medulla-inner
region
• Nephrons
• Functional units
• (~1 million each
kidney)
STEP 1: FILTRATION
Materials filtered from
the blood by the nephron
are called filtrate
1. Water
2. Salts
3. Glucose
4. Amino acids
5. Urea (the waste
product of amino acid
breakdown)
STEP 2: RE-ABSORPTION
• Amino acids, fat, glucose and
most water - returned to the
blood.
• Urine - urea, excess salts and
water; stays in the nephron
STEP 3: EXCRETION
Flow of Urine:
Nephron
Ureters
Urinary bladder
• Average bladder
capacity is 500 ml
(16 oz)
• ~48 gallons of
filtrate are
processed each day;
1% is excreted as
urine (~ .5 gallon)
Urethra
26
HOMEOSTASIS BY MACHINE
• Dialysis - blood is passed through a filtration system
other than the kidneys and returned to the body
Hemodialysis - machine
Peritoneal dialysis