Unit 2 7 th Science NCFE Review.
How are cells organized? Ø Complex living things are organized into 5 levels. Ø Cells carry on the processes that keep us alive. Examples: Red Blood Cells Muscle Cells Skin Cells ORGANISM (BODY) ORGAN SYSTEM ORGANS TISSUES CELLS
What are all living things made of? Ø All living things are made of CELLS! (You have billions of cells inside you.) Ø Cells have specialized jobs, and are organized in your body. Ø For example, these red blood cells carry oxygen around your body in your blood.
What is HOMEOSTASIS? Ø HOMEOSTASIS is how your body maintains an INTERNAL BALANCE. Ø It keeps your body STABLE in spite of changes OUTSIDE YOUR BODY. Ø Example: Your body keeps CONSTANT TEMPERATURE no matter what the outside temperature.
How does your body maintain HOMEOSTASIS? Ø When you are TOO HOT, your body SWEATS to keep you cool. When you are TOO COLD, your body SHIVERS to keep you warm.
Which systems work together? RESPIRATORY SYSTEM gets OXYGEN from the air. DIGESTIVE SYSTEM gets GLUCOSE from food. CIRCULATORY SYSTEM DELIVERS oxygen and glucose to cells. Ø In the cells, respiration uses glucose and oxygen to release ENERGY.
The Digestive System The digestive system has 3 main functions: 1. It breaks down food into particles that the body can use. 2. It absorbs nutrients into the blood. 3. It eliminates waste from the body.
The Digestive System Digestion can happen in two ways: 1. Mechanical digestion: foods are physically broken down into smaller parts (like by teeth). 2. Chemical digestion: Chemicals called ENZYMES break foods into their smaller building blocks (for example, starch gets broken down into sugar).
What does it do for us? Our circulatory system (or cardiovascular system) is made up of the heart, blood vessels, and blood. Delivers necessary materials (like oxygen and sugar) to the entire body in the blood, Removes waste products from cells, and helps fight disease by transporting immune cells in the blood.
How does it move stuff? Your blood travels in two main loops: 1. From the heart to the lungs and back, and 2. From the heart to the body and back.
Blood Flow in the Heart Right Atrium Oxygen-poor blood FROM THE BODY Left Atrium Oxygen-rich blood FROM THE LUNGS Right Ventricle Oxygen-poor blood gets pumped TO LUNGS Left Ventricle Oxygen-rich blood gets pumped TO THE BODY
blood Blood is a fluid connective tissue. Remember, a tissue is a group of cells that all have the same job. What does our blood do for us? Transports materials around your body Fights infection Maintains body temperature (homeostasis!)
What is blood made of? WHITE BLOOD CELL PLATELETS RED BLOOD CELL Red Blood Cells (RBCs) carry oxygen to all parts of the body. White blood cells fight infection and are part of the immune system.
- Breathe in and out What is the FUNCTION of the Respiratory System? To DELIVER OXYGEN to the body. To REMOVE CARBON DIOXIDE from the body.
- Breathe in and out Why does the body need oxygen? The body s CELLS use OXYGEN to release ENERGY to the body. CELLULAR RESPIRATION is the CHEMICAL REACTION that uses GLUCOSE & OXYGEN to release ENERGY. CARBON DIOXIDE is a WASTE PRODUCT of this chemical reaction.
- Breathe in and out What path does AIR follow? NOSE PHARYNX TRACHEA BRONCHIAL TUBES LUNGS (alveoli)
- Breathe in and out How do we BREATHE? INHALATION - the DIAPHRAGM (a large domeshaped muscle at the base of the lungs) contracts and moves DOWN. The RIB CAGE moves UP & OUT. The volume of the lungs INCREASES, and air FLOWS IN.
How do we BREATHE? Ø When you breathe, the actions of your RIB MUSCLES and DIAPHRAGM, expand or contract your chest, changing the VOLUME of your lungs. As a result, AIR rushes in or out.
How are BREATHING & SPEAKING related? Air that you BREATHE OUT when you exhale also helps you SPEAK. Your LARYNX is your VOICE BOX which has 2 VOCAL CHORDS that move and produce sound when air passes through the opening between them. Larynx
The Excretory System How Our Body Eliminates Waste and keeps us healthy! Excretory System = Urinary System
Function: Removes or excretes excess water, H2O, urea, carbon dioxide, CO2, and other wastes from our blood. Importance: Harmful chemicals made when the body creates energy must be removed from blood to keep you healthy
Body Parts that Excrete Waste Kidneys filter out excess water, salt and chemicals as urine Lungs filter out carbon dioxide, CO2, from the blood. (respiratory system) Skin excretes water, as sweat, which contains some trace chemical wastes, including urea. (epidermis)
What is sexual reproduction? Sexual reproduction just means: the female produces an egg the male produces sperm the two sex cells join together during fertilization to produce an offspring. Most organisms on earth sexually reproduce plants, insects, animals, humans, etc... Sexual reproduction makes sure you have a variety of genes half from EACH parent! Having variety is GOOD for the SPECIES!