The Skeletal System

• The characteristics of living things can be remembered by the acronym MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.

The Skeletal System

• The skeleton provides movement by allowing muscles to attach to bones.
• The skeleton offers protection by preventing damage to organs.
• The skeleton provides support by keeping the body upright.
• A bone left in acid becomes rubbery and flexible because the acid removes calcium phosphate.
• A bone heated to a high temperature becomes brittle and breaks easily because the heat removes collagen.
• Osteoporosis is diagnosed through bone density measurement.
• Osteoporosis symptoms include severe back pain, loss of height, or abnormal spine growth.
• Postmenopausal white and Asian women are most at risk of osteoporosis.
• Osteoporosis treatment includes ensuring sufficient calcium and vitamin D intake, along with medicines like Bisphosphonates.
• Osteoporosis can be prevented through regular exercise, a healthy diet, and sun exposure.

Movement - Joints

• Ball & Socket joints feature a rounded head of bone fitting into the socket of another, found in the hip & shoulder.
• Hinge joints function like a door hinge, found in the knee & elbow.
• Fixed joints don’t allow any movement, found in the skull.
• Synovial joints produce fluid to lubricate the joint for smooth movement.
• Cartilage cushions and protects the ends of bones with a smooth, slippery material.
• Ligaments attach bones to bones, while tendons attach muscle to bones.

The Respiratory System

• The epiglottis is a flap that covers the trachea during swallowing to prevent food from blocking it.
• The ribs protect the lungs and heart.
• Cartilage in the trachea prevents collapse and suffocation.
• Breathing rate is the number of breaths per minute.
• Tidal volume is the quantity of air that moves in and out of the lungs during normal breathing.
• Peak flow measures how quickly air can be blown out of the lungs.

The Circulatory System

• Oxygenated blood needs to be pumped around the body

Blood Vessels

• Arteries have thick, muscular walls and carry blood away from the heart under high pressure, which can be felt as a pulse.
• Veins have thin muscular walls, contain valves, and return blood to the heart, with valves preventing backflow.
• Capillaries branch from arteries, forming a network through tissues and organs, reuniting into veins, and have thin walls for substance exchange.

Exercise and Heart Rate Investigation

• Pulse rate increases with exercise.
• Reliability of heart rate testing can be improved by:
  • Ensuring the steps are at the same pace
  • Practicing to take a pulse
  • Repeating the experiment to take an average

Homeostasis

• Homeostasis happens in all living things.
• Organs work together to achieve homeostasis.
• Homeostasis is the maintenance of a stable internal environment.
• When overheated, the body sweats and increases blood flow to the skin to cool down.
• When too cold, the body shivers and decreases blood flow to the skin to generate heat.
• Body temperature must be controlled within a narrow range (37℃) for proper function.
• Homeostasis regulates blood glucose levels to prevent damage to blood vessels.

Homeostasis & Diabetes

• Type 1 diabetes typically affects children, teens, or young adults, with symptoms including increased thirst and frequent urination.
• Type 1 diabetes can be treated with insulin, a healthy diet, and hypoglycemia.
• Type 2 diabetes typically affects those overweight, age 45 or older, or with a family history, with symptoms including thirst, fatigue, and slow-healing cuts.
• Type 2 diabetes can be treated with a good diet, exercise, weight loss, Metformin, Insulin or weight loss surgery

Reproductive System

• During sexual intercourse, the penis releases sperm into the vagina.
• Sperm swim from the vagina through the cervix to the uterus.
• An egg cell can be fertilized by a sperm cell in the oviduct.
• A fertilized egg cell is called a zygote, which develops into an embryo and eventually a baby.
• During pregnancy, the baby receives nutrients and oxygen via the placenta through the umbilical cord.

The Digestive System

• The body needs food.

Digestion

• Break down of food

Enzymes & Digestion

• An enzyme is…

Experiment Review

• Iodine was added to starch:
• Amylase was added to starch: