Skeletal System Concept Notes PDF

Aim: How can we give an accurate overview of the skeletal system? Do Now: Pair/Share: What makes Wolverine’s skeleton unique? Would you want your skeleton or his? Why? Success Criteria: I can list the types of tissue present in a human skeleton I can explain why bones are the function of the skel...

Aim: How can we give an accurate overview of the skeletal system? Do Now: Pair/Share: What makes Wolverine’s skeleton unique? Would you want your skeleton or his? Why? Success Criteria: I can list the types of tissue present in a human skeleton I can explain why bones are the function of the skeletal system Also, it’s not real! Adamantium does not allow for calcium to be absorbed or released into the body Overview • Bone is a rigid but living organ made up of all 4 types of tissues! – Connective tissue: the majority is bone (osseous) tissue but cartilage and dense connective tissue cover the bone’s external surface – Nervous tissue: in its nerves – Epithelial tissue: in its blood vessels, which provide nourishment – Muscle tissue: skeletal muscle tissue Overview • We have 206 bones, making up almost 1/5th of a healthy person’s body weight! – This includes bones, cartilage, ligaments, and joints! • Your skeleton is constantly rebuilding itself – you get a whole new skeleton every 7-10 years!! • More reasons it is awesome: – All other parts of the body would collapse without the skeleton! – We don’t have to worry about our delicate organs (imagine your brain without a skull!!) – Can repair itself once it has been damaged Pair/Share: Come up with a list of why you need your bones. Functions of the Skeletal System • Support – Framework holding up the entire body • Protection – Guards the body’s most vital organs, like the skull protecting the brain and the rib cage protecting the heart • Movement – Skeletal muscles are connected to bones via tendons and use bones as levers at joints to produce movements Functions of the Skeletal System • Storage – Stores minerals like calcium and phosphate, which can be released into the blood when needed – Stores energy in the form of fat in yellow bone marrow • Blood cell formation = hematopoiesis – In red bone marrow of certain bones • Hormone production – Critical for helping to maintain homeostasis • Ex. Produces osteocalcin which regulates insulin secretion, glucose regulation, and energy usage • Ex. Helps to regulate blood calcium levels In your own words, write three distinct reasons with evidence why we need our skeletal system. Success Criteria: I can list the types of tissue present in a human skeleton I can explain why bones are the function of the skeletal system Based on today’s success criteria which skeleton do you identify with and why? 1 2 3 Aim: How can we determine and label the parts of the human skeletal system? Do Now: Write/Pair/Share: share with a partner a function of the skeletal system, write it on the margins of your note packet BIG BODY DIAGRAM (BBD) STATION TIME - You are to choose a partner you have not worked with or sat next to this year. - There are 8 stations around the room - You will need to answer the questions on your lab sheet and label the bones mentioned at the station on your BBD. You will have 7 minutes to finish each station. Aim: How can we classify and determine the structure of bones? Do Now: Pair/Share: Compare and contrast the structure of a cat paw and a human hand Success Criteria: I can give an example of each type of bone classification (short, flat, long, irregular) and its function in the skeleton I can describe the different structures of bones and how they support their function Classification • Bones are classified by their location (in the axial vs. appendicular skeletons) and shape • A bone’s shape dictates its function!! • 4 main types: 1. 2. 3. 4. Long bones Short bones Flat bones Irregular bones Classification 1. Long Bones: longer than they are wide – Tend to have a long shaft with either end being a bit wider – Mostly located in the limbs – Act as levers to aid in movement – Examples: • • • • Arm bones (humerus, radius, and ulna) Hand bones (metacarpals and phalanges) Leg bones (femur, tibia, and fibula) Foot bones (metatarsals and phalanges) Classification 2. Short Bones: more cube shaped – Tend to be as wide as they are long – Provide support and stability with little movement – Examples: • Wrists (carpals) • Ankles (tarsals) – Special type of short bone = sesamoid bones • Means to be shaped like a sesame seed • Are embedded within tendons • Ex. Knee cap (patella) Classification 3. Flat Bones: thin and flat bones – Often have a bit of a curve – Have a large surface area for attaching to muscles – Examples: • • • • Breastbone (sternum) Shoulder blades (scapula) Ribs Most of the cranial bones in the skull Classification 4. Irregular Bones: everything else – Have a highly specialized shape and structure – Examples: • Hip bones • Vertebrae Pair/Share: What are the two types of bone tissue? How are they different? Bone Structure Despite the variety in shape, most bones have the same basic internal structure. • A dense and smooth layer of compact (cortical) bone tissue on the outside surrounding the more porous spongy bone tissue on the inside. Bone Structure • Structure of the compact bone: – Made of osteons = the basic structural unit; long cylinders that act as tiny weight-bearing pillars in the bone. • Made of a group of hollow tubes called lamella – Filled with tiny salts and collagen fibers that allow the bone to resist torsion stress • The Haversian canal (or central canal) runs through the middle of each osteon and contains small blood vessels for nourishment and nerve fibers for signaling. Bone Structure • Structure of the spongy bone: – Less organized than compact bone – No osteons – Do have trabeculae = tiny bone struts that are key for helping the bone to resist stress; also where bone marrow is • Remember: Red bone marrow makes blood cells and yellow bone marrow stores energy in the form of fat! Bone Structure • The external surface of a bone is rarely smooth, and often has distinct bone markings that correspond to how the bone and its attached muscles and ligaments work together. • 3 types of markings: – Projections where muscle and ligaments attach – Surfaces that form joints – Depressions and openings for blood vessels and nerves to run through Success Criteria: I can give an example of each type of bone classification (short, flat, long, irregular) and its function in the skeleton I can describe the different structures of bones and how they support their function Which skull represents your ability to answer today’s success criteria? Why? 1 2 3 Aim: How are bones formed and repaired in our bodies? Do Now: Pair/Share: Compare and contrast these two images. What similarities and differences do you notice? What bones can you identify? Success Criteria: I can list and explain the stages in bone formation I can list and explain the stages in bone remodeling Update: We probably won’t find out what happened to this patient as she was between 11-14 years old at the time of the car accident. Bone Cells • Osteocytes: maintain healthy bone structure – Housed in the lacunae = gaps between the lamellae • Think of them as like the foremen at a construction site – they monitor, maintain quality, and command the workers (which in this case are the osteoblasts and osteoclasts) in response to stimuli (like stress, strain, or a lack thereof like astronauts experience) • Osteoblasts: build and construct bones by calcifying bone as it forms • Osteoclasts: critical in the regeneration of bone through bone remodeling by absorbing bone tissue wherever it is not needed or is degenerating Bone Formation • Ossification (osteogenesis) = the process of bone tissue formation – Key for forming your skeleton as an embryo (beginning at week 8) – Essential for bone growth from childhood up until early adulthood – Later in life is used for bone remodeling and repair • Two Types: – Intramembranous ossification = bone develops from a fibrous membrane 🡪 membranous bone; Ex. Clavicle and skull bones – Endochondral ossification = bone develops by replacing cartilage 🡪 endochondral bone; Ex. all other bones • Cartilage remains in 2 places – the articular cartilage on the ends of bones and the epiphyseal plates which is where bone growth comes from as bones elongate Endochondral ossification = bone develops by replacing cartilage Pair/Share: What can we notice about the changes in bone and cartilage here? Bone Remodeling • Bone is constantly being remodeled – This is important because if it didn’t happen, the calcium in our bones would crystallize and make the bones more brittle 🡪 more likely to fracture • The Process: – Osteocytes release chemical signals to tell osteoclasts to go to the damage. – Osteoclasts release enzymes there that allow them to digest the calcium phosphate, putting the calcium and phosphate back into the blood = resorption – Macrophages promote bone tissue remodeling. – Osteoblasts come in and build new bone before they undergo apoptosis Bone Damage • Fracture = Break • Treatment = reduction (realignment of the broken bone ends) and immobilization (keeping bone stable so it has time to heal itself) Bone Damage • Repair = – Hematoma forms due to hemorrhaged blood clots (from where blood vessels in the bone were torn during the break) – Fibrocartilaginous callus forms that spans the break and connects the broken ends – Osteoblasts begin forming spongy bone and replacing the cartilaginous callus – Bone remodeling occurs Success Criteria: I can list and explain the stages in bone formation I can list and explain the stages in bone remodeling Based on today’s Success Criteria: Which bone do you identify with? Why?