Human Biology Notes: Digestive & Other Systems

Functions of the digestive system -Breaks down food into usable molecules -Absorbs nutrients into the bloodstream -Eliminates waste from the body -Definition: Digestion is the process of breaking down food into small nutrient molecules Types of digestion: Mechanical Digestion -Physical breakdown of...

Functions of the digestive system -Breaks down food into usable molecules -Absorbs nutrients into the bloodstream -Eliminates waste from the body -Definition: Digestion is the process of breaking down food into small nutrient molecules Types of digestion: Mechanical Digestion -Physical breakdown of food into smaller pieces -Example: Chewing a sandwich. Chemical digestion -Chemicals in the body break food into smaller chemical building blocks -Carried out by enzymes Absorption and Elimination -Absorption: Nutrient molecules pass through the digestive system wall into the blood. Eliminations: Materials that are not absorbed are removed as waste The mouth: Where digestion begins -Both mechanical and chemical digestion start here -Saliva plays a key role in both processes. -Teeth perform mechanical digestion: -Incisors and canines for tearing -Premolars and molars: For Grinding Chemical Digestion: Enzymes in saliva begin breaking down food. Your teeth are NOT made of bone. Unlike bones, which have plenty of blood vessels running through them, tooth enamel doesn't have a way to get fresh oxygen and nutrients. The Esophagus: Foods Highway Muscular tube connecting the mouth to the stomach -Lined with mucus for easier swallowing -Food stays there for about 10 seconds -Peristalsis: Involuntary muscle contracts that push food down. The stomach: Nature mixer -J-shaped muscular pouch in the abdomen -Stretches to accommodate food -Mechanical digestion: Strong muscles inside the stomach create a churning motion -Chemical digestion: -Pepsin breaks down proteins -Hydrochloric acid kills bacteria Stomach protection: -Hydrochloric acid is very strong -The stomach lining is coated with thick mucus that prevents acids from damaging the stomach 2-4: Final Digestion The Small intestine -The small intestine is about 6 meters long -Is where most chemical digestion occurs -Absorbs most nutrients from food -Contains millions of tiny structures called villi -Villi increases surface area for better absorption Helpers of the Small Intestine -Liver: produces bile to break down fats -Gallbladder: Stores bile until needed -Pancreas: Make enzymes to break down Starches Proteins Fats The Mighty liver -Largest internal organ -Located in the upper right abdomen -Main digestive job: Produces bile -Bile breaks fat into smaller droplets -Stored in the gallbladder until needed The hardworking Pancreas Triangular organ between the stomach and the small intestine -Produces important digestive enzymes -Enzymes flow into the small intestine -Helps break down: Starches Proteins Fats Villi: Tiny Nutrient Absorbers Millions of finger-like structures -Line the small intestine -Increase surface area for absorption -Absorb Nutrient molecules -Pass nutrients to blood vessels -Blood carries nutrients to all body cells The large intestine: The final stretch -Last section of the digestive system -Contains helpful bacteria -Most nutrients are already absorbed before reaching here -Absorbs water from remaining material -Prepares waste for elimination What happens in the large intestine -Receives water and undigested food -Absorbs water into the bloodstream -Compresses remaining waste -Helpful bacteria feed on leftover material The End of the Journey -Rectum: Short tube at the end of the large intestine -Compact waste into solid form -Anus Muscular opening for waste removal -Solid waste leaves the body through the anus -Liquid waste leaves as urine Axons are primarily involved in sending signals away from the neuron, while dendrites are focused on receiving incoming signals. 1. The cerebrum helps you think and make plans for riding a bike, like how to pedal and steer. The cerebellum helps you balance and coordinate your movements. Together, they make it easier for you to ride smoothly and stay stable. 2. The autonomic nervous system (ANS) controls functions we don't think about, like heartbeats and breathing. 3. The brain won't be able to send signals to move or react to the cut-off part of the spinal cord, resulting in partial or full paralysis. 4. Nearsightedness makes faraway objects blurry because light focuses in front of the retina. Glasses with thin, concave lenses spread the light out so it focuses correctly on the retina. Farsightedness makes nearby objects blurry because light focuses behind the retina. Glasses with thick, convex lenses bend because the light is bent inward to focus it properly on the retina. 5. Eardrum, Ossicles, Malleus, Incus, Stapes, Oval window, coclea, Hair cells, Auditory Nerve. 6. It can lead to heart issues, liver damage, and mood changes. It can also lead to bad skin and unwanted hair growth. 7. The gases help them pass over 8. The left side of the brain is where it happened 9. This is an example of a reflex. This protects his food from getting more damaged and/or hurt. 10.You can die from taking drugs. This argument would show how keen I am NOT to take drugs. 11.100 on the Y-axis, and 10 on the X. 12.It gets lower 13.The manipulated variable is the distance, the responding variable is the letters. 14.A farsighted person would have better letter identification from afar, and if the distance remained the same, the line would go from down to up. 1. a regulate its activities B. makes it beat faster, making it pump more blood to the body C. You could die. 2a. Hypothamus, pituitary, thyroid, parathyroid, adrenal, thymus, and pancreas. They also include the ovaries in females and testes in males. B. They link between two systems.s C. The hypothalamus helps control growth from infancy to adulthood by releasing a hormone that tells the pituitary gland to produce Growth Hormone 3a. Negative feedback tells your body you have already made enough of that hormone and that your body needs to stop producing it B. If you get too hot, you start sweating to cool down. Once your temperature is back to normal, negative feedback makes the sweating stop, helping everything stay balanced. The Menstrual Cycle The monthly cycle of change that occurs in females is called menstruation or the menstrual cycle. The average length is 28 days, and it is controlled by both the reproductive system and hormones in the endocrine system. The two basic purposes of the menstrual cycle are to develop and release an egg for fertilization and to prepare the uterus to receive a fertilized egg. The female sex cells are held in a little pocket of cells called a follicle. If the egg within the follicle is matured or ripened, it is released in an ovulation process. The egg then makes its way down the fallopian tubes and into the uterus. In sperm are present, then the lining of the uterus and the egg will begin to break down and pass through the vagina. The average cycle lasts five days. While this is happening, a new egg is maturing in the ovaries, and hormones allow the cycle to start again. 1. A: Fertilization is when the egg and sperm come together B: They combine and create a new person C: Sex cells have 23 chromosomes; a zygote has 46 chromosomes because it has both sex cells 2. A: Male: Its structures include the testes, scrotum, and penis. Female: reproductive system include the ovaries, fallopian tubes, uterus and vagina B: Producing sperm. To mature and release eggs. C: They both work together to fertilize the egg. They have different purposes 3. A. The period when a female releases the unfertilized egg. B. Before.