UNIT 3 – PART 1

1C I RC U L AT O RY & E XC R E T O RY S Y S T E M S

UNIT 3 – PART 1

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THE CIRCULATORY SYSTEM

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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

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PARTS

•Heart•Blood Vessels•Blood

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COMPONENTS OF BLOOD

• Red blood cells•White blood cells• Platelets• Plasma

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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

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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

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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

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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)

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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

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TYPES OF BLOOD VESSELS

• Arteries• Large and thick-walled• Carry blood from the heart to the rest of the body

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TYPES OF BLOOD VESSELS

• Veins• Smaller than arteries and not as

thick-walled• Carry blood from the rest of the

body back to the heart

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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

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THE HEART

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BLOOD FLOW THROUGH THE HEART

• Oxygen poor-1.) Superior and inferior vena cava2.) Right Atrium

3.) Right Ventricle

4.) Lungs

• Oxygen rich-5.) Left Atrium

6.) Left Ventricle

7.) Aorta

8.) Body

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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

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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

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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 blood2. 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 filtrate1. Water2. Salts3. Glucose4. Amino acids5. 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

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STEP 3: EXCRETION

Flow of Urine: Nephron

Ureters Urinary bladder

Urethra

• Average bladder capacity is 500 ml (16 oz)• ~48 gallons of

filtrate are processed each day; 1% is excreted as urine (~ .5 gallon)

HOMEOSTASIS BY MACHINE

• Dialysis - blood is passed through a filtration system other than the kidneys and returned to the body

Hemodialysis - machine Peritoneal dialysis