Unit 5 Study - Bio

  • Sensory neurons: Nerve cells that carry signals from sense organs to the brain or spinal cord.

  • Motor neurons: Nerve cells that carry signals from the brain or spinal cord to muscles.

  • Diaphragm: A muscle under the lungs that helps with breathing.

  • Hemoglobin: A protein in red blood cells that carries oxygen.

  • Chemoreceptors: Cells that detect chemical changes, like oxygen or carbon dioxide levels.

  • Antibody: A protein made by the immune system to fight pathogens.

  • Genetic engineering: Changing an organism’s DNA to give it new traits.

  • Substrate: The substance an enzyme acts on.

  • Pathogen: A microbe that causes disease.

  • Enzymes: Proteins that speed up chemical reactions in the body.

  • Purpose of enzymes: They speed up chemical reactions in the body.

  • Used up?: No, enzymes are not used up; they can be reused.

  • How they work: They bind to a substrate and lower the activation energy needed for the reaction.

  • Two environmental factors: Temperature and pH; they affect the enzyme’s shape and activity.

  • ATP: A molecule that stores and provides energy for cell processes.

  • The purpose of mitosis is to make new, identical cells for growth, repair, and replacement.

  • Circulatory system: Blood flow was blocked in his trapped arm, causing tissue damage.

  • Endocrine system: Stress hormones like adrenaline and cortisol increased to help him survive.

  • Excretory system: Dehydration affected kidney function and reduced urine output.

  • Nervous system: Pain signals, decision-making, and survival instincts were highly active.

  • Purpose of hormones: They send chemical messages to control body functions like growth, metabolism, and mood.

  • How the endocrine system works: Glands release hormones into the blood, which travel to target organs.

  • Hypothalamus: It links the nervous and endocrine systems and controls hormone release from the pituitary gland.

  • Purpose of the circulatory system: To transport oxygen, nutrients, hormones, and waste through the body.

  • Heart chambers: 4 chambers – 2 atria and 2 ventricles.

  • Pathway of blood:
    Body → right atrium → right ventricle → lungs (gets oxygen) → left atrium → left ventricle → body

  • Parts of blood:

    • Red blood cells – carry oxygen

    • White blood cells – fight infection

    • Platelets – help clot blood

    • Plasma – carries nutrients, hormones, and waste

  • Types of blood vessels:

    • Arteries – carry blood away from the heart

    • Veins – carry blood back to the heart

    • Capillaries – exchange gases and nutrients with cells

  • Red blood cells: Carry oxygen using hemoglobin.

  • White blood cells: Defend the body against infections.

  • Platelets: Help blood clot to stop bleeding.

  • Function of the digestive system: Breaks down food to absorb nutrients and eliminate waste.

  • Two types of digestion:

    • Mechanical digestion: Physical breakdown of food (e.g., chewing, stomach churning)

    • Chemical digestion: Breaking down food with enzymes and acids (e.g., saliva, stomach acid, pancreatic enzymes)

  • Where nutrients are absorbed: Mostly in the small intestine.

  • Systems it coordinates with: The circulatory system (for nutrient transport) and the nervous system (for regulating digestion).

Path of food through the alimentary canal:

  1. Mouth: Chewing (mechanical) and saliva (chemical) start digestion.

  2. Esophagus: Moves food to the stomach through peristalsis.

  3. Stomach: Churns food and mixes it with stomach acid and enzymes (chemical digestion).

  4. Small intestine: Most digestion and nutrient absorption occur here (with enzymes from the pancreas and bile from the liver).

  5. Large intestine: Absorbs water and salts; forms solid waste.

  6. Rectum & Anus: Expels waste.

    Henrietta Lacks contributed to scientific research through her cancer cells, known as HeLa cells, which were taken without her consent in 1951. These cells became vital in medical research, helping to develop vaccines, cancer treatments, and understanding genetics.

    She received recognition posthumously, especially after her story gained attention through the book The Immortal Life of Henrietta Lacks. Her family also began receiving more acknowledgment in recent years.

  7. Purpose of the respiratory system: To bring in oxygen and remove carbon dioxide from the body.

  8. Where gas exchange occurs: In the alveoli of the lungs.

  9. System it coordinates with: The circulatory system (for transporting gases to and from cells).

3 phases of respiration:

  1. Ventilation: The movement of air into and out of the lungs (breathing).

  2. External respiration: Gas exchange between the air in the alveoli and the blood in the capillaries (oxygen in, carbon dioxide out).

  3. Internal respiration: Gas exchange between the blood and the body's cells (oxygen out, carbon dioxide in).

  • Purpose of the excretory system: To remove waste and excess substances from the body, maintaining internal balance (homeostasis).

  • Components and what they excrete:

    • Kidneys: Filter waste (like urea) from the blood, excrete urine.

    • Ureters: Transport urine from kidneys to the bladder.

    • Bladder: Stores urine.

    • Urethra: Expels urine from the body.

  • Nephrons: Functional units of the kidney that filter blood and produce urine.

  • What can be done when kidneys are damaged:

    • Dialysis: A machine filters waste from the blood when kidneys fail.

    • Kidney transplant: Replacing a damaged kidney with a healthy one.

  • System it coordinates with: The circulatory system (for filtering blood) and the nervous system (for regulating water balance and waste removal).

  • 1st line of nonspecific defense:

    • Physical barriers: Skin and mucous membranes (block entry of pathogens).

    • Chemical barriers: Enzymes in saliva, tears, and stomach acid (kill or inhibit pathogens).

    • Biological barriers: Normal flora (good bacteria) that outcompete harmful microbes.

  • Other nonspecific defenses:

    • Phagocytes: White blood cells that engulf and destroy pathogens.

    • Natural killer cells: Attack infected or cancerous cells.

    • Complement system: Proteins that help destroy pathogens and promote inflammation.

  • Purpose of fever: It raises body temperature to help kill pathogens and enhance immune response.

  • How the inflammatory response works:
    When tissue is injured, it releases chemicals (like histamine) that increase blood flow, causing redness and swelling. This helps deliver immune cells to the area to fight infection and start healing.

  • A vaccine works by introducing a harmless part of a pathogen (like a protein or inactivated virus) into the body. This stimulates the immune system to produce antibodies and memory cells, so if the body encounters the actual pathogen later, it can respond quickly and effectively.