Chapter 23: Digestive, Muscular and Skeletal Systems PDF

Chapter 23: Digestive, Muscular and Skeletal Systems SCB 101 Prof. Calkins  Micronutrients: Support growth and function of vitamins and our bodies and aid in everyday...

Chapter 23: Digestive, Muscular and Skeletal Systems SCB 101 Prof. Calkins  Micronutrients: Support growth and function of vitamins and our bodies and aid in everyday minerals functions Nutrients Macronutrients: Serve as chemical Large organic building blocks for cell structures molecules; three Provide ENERGY main biomolecules Water Water is necessary for all cellular activities! How do we use water to maintain homeostasis? Blood Pressure, eliminate solid waste, maintain temperature You can only survive a few days without water How do you lose water? Sweat, urine, feces To replace this water lost, you need to take in about 12 cups a day Recap What are the four main biomolecules that are essential to all living things? Carbohydrates Lipids Proteins Nucleic Acids 1. Proteins Made of amino acids Regulate chemical reactions in cells Make up the structural parts of cells 2. Carbohydrates Made of sugars Food source (glucose, starch..) Plant cell wall (cellulose) 3. Lipids Made of glycerol and fatty acids Energy source Insulate body Make up cell membrane 4. Nucleic Acids Made of nucleotides Make up DNA  Vitamins: coenzymes that regulate chemical pathways Vitamins, Minerals: important for bone and tooth Minerals, and development, muscle contraction, nerve impulses, and fluid balance Dietary Fibers Fiber: indigestible carbohydrate that cleanses digestive system Vitamins Small organic micronutrients Help regulate chemical pathways Minerals More than 20 minerals are needed for human health. Calcium is the most abundant and is stored in your bones. Vitamin D is needed to absorb calcium from food, as well as for bone health. Low levels of vitamin D result in bone disorders and a wide range of diseases. Recap: Why do we need to eat a variety of foods? a. It’s too boring to eat the same thing all the time. b. No single food provides everything we need to be healthy. c. You tend to overeat if you eat just one thing. d. No single food contains enough energy to run a body The Digestive System The digestive system absorbs vitamins, processes foods and nutrients, and eliminates waste Starts with ingestion, or taking in food by the digestive system Then digestion, the chemical breakdown of food The Digestive System As food moves through the digestive system, it is broken down into small molecules that can be absorbed by the lining of the intestine Oral cavity: mouth Saliva: contains enzymes to break apart carbs Pharynx: throat The common area leading to trachea (airway) and the esophagus (food tube) Swallowing reflex causes epiglottis (cartilage flap) to seal the trachea The Digestive System Stomach: where some digestion begins Small intestine: where most absorption occurs Large intestine: colon Absorbs water and minerals Hosts bacteria that produce vitamins Absorption: the uptake of mineral ions—including calcium—and small molecules by cells lining the cavity of the digestive tract  The small intestine is specialized with a large surface area for The Small absorption of the uptake of minerals, certain vitamins, and small molecules. Villi: fingerlike projections in the small intestine that absorb nutrients Intestine The plasma membrane of each cell of the villi has many tiny projections, called microvilli. Pancreas, Liver and Gallbladder Pancreas: gland-secreting digestive enzymes Liver: produces bile Bile: fluid aiding in fat digestion Gallbladder: stores and dispenses bile to small intestine  Recap: Why is a larger surface area important for absorption? The Human Skeleton The axial human skeleton protects vital organs. The appendicular skeleton facilitates movement.  At the joints, bones are held together by: Ligaments: flexible bands of connective tissue linking bone Joints to bone Tendons: bands of connective tissue rich in collagen linking muscle to bone  Muscular System Muscle tissue is unique to animals. It can contract and relax, causing movement. Muscle fiber: A long, narrow cell that can span the length of an entire muscle Made up of several muscle cells that fused together during development Voluntary muscles: Under conscious control Skeletal muscle: Causes movement of the skeleton Consists of many bundles of muscle fibers Involuntary muscles: Under unconscious control Cardiac muscle: Only found in vertebrate heart Smooth muscle: The digestive tract, the walls of blood vessels, the respiratory tract, the uterus, and the urinary bladder  Both ends of a skeletal muscle are anchored by tendons to nearby bones as support structures. The Muscles A muscle contains bundles of muscle fibers, each one That Move You running the length of the entire muscle. Recap: Q1: How is skeletal muscle attached to bones in the skeleton? Tendons Q2: Do skeletal muscles contract voluntarily or involuntarily? Voluntarily Q3: Is a muscle fiber one cell or multiple cells? Multiple cells that fused together during development