Savvas Realize Science Course 2 Topic 2

Body Organization

• Similar cells that perform the same function are grouped together to form a tissue. Ex: Muscle, Nervous, Connective, Epithelial

• An organ is a body structure that is composed of different kinds of tissues.

• An organ system is a group of organs that work together.

A: Control Systems

• The nervous system, made up of the brain, spinal cord, and nerves, sends information through nerve cells to control your actions.

• The endocrine system is a collection of glands that produce hormones.

B: Structural Systems

• The skeletal system includes your bones and connective tissue which support and protect the body.

• The muscular system controls your movement and the integumentary system (skin, hair, nails) protects the body from outside damage.

C: Oxygen & Transport Systems

• The respiratory system brings in oxygen and moves out carbon dioxide.

• The circulatory system carries oxygen-rich blood throughout the body.

D: Food & Waste Processing Systems

• The digestive system breaks down food.

• The excretory system gets rid of waste products and toxic substances.

E: Defense (Immune) System

• The immune system is your defense system against infection. (Ex: Lymph nodes, Lymph Vessels, White Blood Cells)

F: Reproductive System

• The reproductive system is responsible for producing sperm and eggs, and nurturing the fetus until birth. (Testes, penis, ovaries, uterus, vagina)

Stimulus and Response

• Any change or signal in the environment that can make an organism react is called a stimulus.

• A response is an action or change in behavior that occurs as a result of a stimulus

Managing Stress

• Stress is the reaction of a person's body to potentially threatening, challenging, or disturbing events.

• Ongoing stress can disrupt homeostasis, weaken the immune system, and cause other health issues.

Fighting Disease

• To fight disease, the body devotes resources to the immune system and its specialized cells.

Digestion and Nutrients

• Digestion is the process by which the body breaks down food into smaller nutrient molecules.

• Nutrients are substances in food that provide the raw materials the body's cells need to carry out their essential processes.

Carbohydrates

A carbohydrate is an energy-rich organic compound, such as a sugar or starch, made up of the elements carbon, hydrogen, and oxygen.

They can be quickly broken down to release energy in the form of calories.

There are 2 kinds of carbs:

• Simple carbohydrates are smaller molecules and taste sweet. (sugars)

• Complex carbohydrates, such as fiber, are larger molecules. (starches, Whole Grains)

Proteins

• Proteins, made up of amino acids, are needed for growth and body repair. Ex: animal sources, beans, nuts

Fats

Fats provide a concentrated energy source and are used for long-term energy storage.

Two types of fat, saturated & unsaturated:

• Saturated fat comes from animal products and are solid at room temp.

• Unsaturated fat comes from plant products and are oils (olive oil). They are liquid at room temp.

Vitamins

Vitamins are nutrients that help your body with necessary chemical reactions, but do not provide energy.

Your body can make some vitamins, but most have to be taken in through diet.

There are two kinds of vitamins:

• Fat-soluble vitamins (A+K) are stored in the fatty tissues of the body and are released when needed.

• Water-soluble vitamins (C) dissolve in water and are not stored in large amounts.

Minerals

• Minerals are nutrients not made by the body, but are needed in chemical processes. Ex: Iron (meat + leafy greens) are used for blood

Water

• Water is the most important nutrient. Survival time w/ out water depends on both environmental conditions and the level of activity.

Type A: Mechanical Digestion

• Mechanical digestion involves the physical breakdown and movement of food.

• Food is broken down in the mouth and stomach, and is moved through the esophagus + intestines.

• Waves of smooth muscle contractions that move food through the esophagus are called peristalsis.

Type B: Chemical Digestion

• Chemical digestion involves the chemical breakdown of food.

• It begins in the mouth where saliva is released from glands containing chemicals called enzymes.

• Enzymes are proteins that speed up chemical reactions, causing the food to break down faster.(acts on starch)

• Chemical digestion continues in the stomach where enzymes + hydrochloric acid further break down food. Then, it continues onto the small intestine.

The Small Intestine, Liver, and Pancreas

• The majority of chemical digestion and nutrient absorption takes place in the small intestine. The liver and pancreas secrete enzymes to aid in breaking down fats and any remaining carbs+proteins.

• The liver produces an enzyme called bile which breaks down fat into smaller fat droplets to be digested.

• Bile is stored in the gallbladder, and is released into the small intestine. The liver also filters blood and stores vitamins.

• The pancreas produces an enzyme called trypsin, which breaks down proteins. it also makes insulin to monitor blood sugar.

The Large Intestine

• In the large intestine, water is reabsorbed from food, and waste products are compacted and prepared for elimination.

• Waste is collected in the rectum and is eliminated through the anus.

The Circulatory System

• Transports nutrients, oxygen and waste; helps fight disease.

• Includes the cardiovascular and lymphatic systems.

• Main structure is the heart

The Cardiovascular System

• The part of the circulatory system that pumps blood throughout the body

The Path of Blood

• Oxygen-rich blood travels from the lungs to the left atrium, down to the left ventricle to be pumped throughout the body.

• It delivers nutrients + oxygen to the body's cells, in which it picks up waste products (carbon dioxide).

• The oxygen-poor blood returns through the right atrium, down to the right ventricle, and out to the lungs where gas is exchanged.

Double Loop System

• In loop 1, blood travels from the heart to the lungs and back to the heart.

• In loop 2, oxygenated blood moves from the heart, out to the body, and deoxygenated blood returns to the heart.

Red Blood Cells

• Red blood cells deliver oxygen and absorb carbon dioxide from cells.

Blood Vessels

• The heart is connected to the body by a system of blood vessels:

• Arteries carry blood away from the heart.

• Veins carry blood back to the heart.

• Capillaries are tiny vessels where substances are exchanged between the blood and body cells. (connect a + v)

Diffusion in Blood

• Oxygen and other materials move through capillary walls by diffusion (high to low c.) Ex: As blood contains more glucose than cells, it diffuses into them.

Blood Pressure

• The force with which the ventricles of the heart contract to pump blood throughout the body (heartbeat)

Blood

• Made up of red blood cells, white blood cells, plasma, and platelets:

• White blood cells fight disease.

• Platelets help clot wounds.

• Plasma is the liquid part of blood.

The Lymphatic System

• A network of vessels that return fluid to the bloodstream. Fluid in the lymphatic system (lymph: water, wbc, mt) flows through lymph vessels. They connect to lymph nodes that filter and trap bacteria.

The Respiratory System

• Brings in oxygen, removes carbon dioxide.

• Main organs are the lungs, but also includes:

• The nose, which moistens the air.

• Trachea (windpipe)

• The bronchi (two passages that direct air into the lungs)

• Alveoli (sacs of lung tissue where gas is exchanged

Breathing Process

When you inhale, your rib muscle + diaphragm contract, the chest moves up and outward, and air pressure lowers. The opposite happens when you exhale.

Gas Exchange (Alveoli)

• Oxygen in the alveoli passes through the capillary walls into the blood. Carbon dioxide and water pass from the blood into the alveoli.

Excretory System/Kidneys

• Removes waste from the body.

• The kidneys filter blood and regulate water. They help remove water and urea (chemical from the breakdown of proteins) in urine.

• Kidneys are composed of nephrons, small filtering structures that remove waste from blood and produce urine. First, they filter waste from blood and produce urine. Next, needed materials are returned to the blood and waste is excreted.

Systems That Work Together

• The respiratory, digestive, and integumentary systems work with the excretory system to remove waste from the body to maintain homeostasis.

The Nervous System

• Maintains homeostasis through nerve impulses.

• Includes the brain, spinal cord, and nerves.

• Controls body functions in two ways: electrical signals from nerves, and chemical signals from the endocrine system.

Neurons

A neuron is a nerve cell that carries information through the nervous system. Made up of dendrites and axons.

Three kinds of neurons:

• Sensory neurons pick up a stimulus from the environment and converts it to a message.

• An interneuron carries the message from one neuron to another.

• A motor neuron sends the message to a muscle or gland.

Axons, Dendrites, Synapses

• A dendrite is a branched structure that receives information. The nerve impulse (message carried by the neuron) is sent to the axon, where it is transmitted to nearby cells.

• A synapse is the junction where impulses are transferred between neurons.

• At the axon tips, electrical signals change into the chemical signals (to bridge the gap), and back into electrical.

CNS

• The central nervous system (CNS) controls the functions of the body.

• The brain controls most of the functions of the body, contains interneurons, and has 3 main components:

• The cerebrum interprets input from your senses, controls movement, and carries out mental processes.

• The cerebellum coordinates muscle actions and keeps balance.

• The brainstem controls involuntary actions.

• The spinal cord is a thick column of nervous tissue that links the brain to most of the nerves throughout the body.

PNS

• The peripheral nervous system (PNS) is a network of nerves that connect the CNS to the rest of the body. It has 43 pairs of nerves (12 in the brain, 31 pairs branch out from the spinal cord), and controls your actions.

• Each spinal nerve has both sensory neurons (that bring impulses to the CNS) and motor neurons (that carry impulses away from the CNS)

PNS: Somatic and Autonomic Systems, Reflexes

• The PNS has two groups of nerves. The somatic nervous system controls voluntary actions. The autonomic system controls involuntary actions.

• An automatic response that you cannot control is called a reflex.

Reflex Arc

• Pain can trigger a response known as a reflex arc.

• Sensory neurons detect a pain stimulus and send an impulse to your spinal cord. Interneurons carry the impulse to motor neurons, which direct a response.

• At the same time, impulses travel to the brain to be stored as memories.

The Endocrine System

• Maintains homeostasis by releasing hormones (chemicals that regulate the body).

• Made up of glands (an organ that produces and releases chemicals either through ducts or directly into the bloodstream).

Endocrine Regulators

• The hypothalamus links the nervous + endocrine systems, and is located deep in the brain, above the spinal cord. It sends out nerve signals to control basic body processes (sleep, hunger), and chemical signals. It also produces hormones.

• The pituitary gland receives signals from the hypothalamus and controls other endocrine glands by releasing hormones. It regulates processes including growth, blood pressure, and water balance.

Negative Feedback

• The ES maintains homeostasis by turning off the release of a hormone when they are no longer needed. This process is called negative feedback.

Homeostasis

Homeostasis is a stable internal environment (98.6°F; 37°C):

• Temperature: When your body temp falls to low or high, the nervous system sends signals to other systems to take action (goosebumps, shivering).

• Balance: The brain detects you are off balance through structures in your inner ear. Then, it sends messages to your muscles to keep you steady.

• Energy/Food: When cells need energy, hormones from the ES signal the NS to make you feel hungry.

• Water: When cells need water, the nervous system causes you to feel thirsty. Your senses, muscles, and skeleton take you to a source of water. Thrist ends.