The Excretory System

The Human Excretory System Human metabolism produces a lot of waste Lungs eliminate CO 2 Digestive system produces solid waste which is eliminated by large intestine Kidneys make urine

Kidneys are filters that remove wastes from blood Prevent buildup of wastes Help maintain the body’s internal environment by controlling the volume, composition and pressure of body fluids

Function of the Kidney Nephrons act as filters Each nephron is surrounded by capillaries, this close contact allows exchanges to occur by diffusion they keep the good stuff in: blood cellsGlucose SodiumProteins Some water

Function of the Kidney and let out the bad: – Urea – Wastes – some water

What Happens to the Waste? Urine travels to bladder via tubes called ureters Urine is temporarily stored in the bladder

What Happens to the Waste? When about 200mL urine fill the bladder it stretches and a nerve impulse is sent to the brain signaling the need to go If you ignore the warnings, bladder gets filled to 400mL then sends an urgent message to the brain If you keep ignoring the warnings, once you get to 600mL, you lose voluntary control (but you are probably beyond caring at that point! ;)

What Happens to the Waste? Urine enters the Urethra and is expelled from the body Urethra: tube from the bladder leading outside the body

The Musculoskeletal System

Musculoskeletal system Muscular system Skeletal System

Function of the Skeletal System -Protection -protect vital organs in the body (eg. skull protects brain, spine protects spinal cord, ribs protect heart and lungs -Blood-cell production -bone marrow in large bones produce blood cells and releases them into the blood stream. LONG BONES and flat bones(pelvic & ribs)

Function of the Skeletal System Mineral storage – bones made up of calcium and phosphorus giving bones strength and rigidity. Support for your muscles Movement

Components of the Skeletal System The skeleton is composed of 3 types of connective tissue. – Bone – Ligaments – Cartilage

Bone The human skeleton is composed of 206 bones Hard and dense tissue Bone is composed of bone cells within a matrix of minerals (calcium, phosphorus) and collagen fibers If your diet is not high in minerals, your body will absorb Ca and P from your bones causing them to weaken

Structure of Bone -Canals inside the bones contain nerves and blood vessels -Only a small percentage of the bone tissue is actually living

Ossification process of bone formation, in which connective tissues, such as cartilage are turned to bone or bone-like tissue. ossified tissue have canals that blood vessels run through and bring minerals like calcium and deposit it in the ossifying tissue. dynamic process, with cells called osteoblasts depositing minerals, and osteoclasts removing bone. Ossification continues until late teens or early twenties

Ossification in a Foetus Ossification continues until early adult years This explains the soft spot on a baby’s head Kids have more bones than adults do because as a child grows, its bones fuse together.

How does it all connect? The skeletal system is held together and to other structures by connective tissue. Tendons Ligaments Muscles Cartilage

Ligaments -are strong tough elastic bands of connective tissue that can stretch -Hold bones and movable joints together -surround the joint to give support and limit the joint's movement.

Cartilage hard but slippery tissue that covers the ends of bones where they meet to form a joint. made up of cells and collagen fibres and is wear-resistant helps reduce the friction of movement by allowing bones to glide over one another Absorbs the energy from the shock of physical movement Found in: – Ears, nose, esophagus, joints, disks between vertebrae

Joints place in a skeleton where two or more bones meet

Types of Joints -Immovable joints -Also called sutures -where bones are joined tightly allowing for little or no movement (eg. Skull) -Movable joints -allow for movement

Tendons another type of tough connective tissue on each side of a joint attach to muscles that control movement of the joint.

The Muscular System

Muscles Bones need muscles to move them There are about 600 muscles in the human body Made up of bundles of long cells called muscle fibres that contain specialized proteins Muscle Function contraction for locomotion and skeletal movement contraction for propulsion contraction for pressure regulation

Types of Muscles Cardiac Muscle – Makes heart beat – Controlled by autonomic nervous system Smooth Muscle – Controlled automatically – Found in lining of organs (eg. stomach, esophagus, uterus, walls of blood vessels) Skeletal Muscle – Attached to bone – Conscious control

Muscle Attachment Muscles usually attached to two bones, one movable, one stationary Origin – Place where the muscle attaches to the stationary bone Insertion – Place where the muscle is attached to the moving bone

Antagonistic Muscles Muscles can pull but cannot push so many muscles arranged in pairs that work against each other to make joints move Flexor – muscle that contracts to bend a joint Extensor – muscle that contracts to straighten a joint

Antagonistic Muscles E.g. bicep/tricep Bicep contracts, tricep relaxes, bones of elbow joint close together  bicep is a flexor Bicep relaxes, tricep contracts, bones of the elbow joint far apart  tricep is an extensor