IB Standards / Review Annie Lee, Sarah Bartley, Lauren Thames.
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Transcript of IB Standards / Review Annie Lee, Sarah Bartley, Lauren Thames.
IB Standards / Review
Annie Lee, Sarah Bartley, Lauren Thames
Skeletons
The three main functions of a skeleton: support, protection, and movement (11.2.1)
A hard skeleton provides protection for soft tissues and provides a framework for our bodies.– Name some examples?
Three types of skeletons– Hydrostatic skeletons, Exoskeletons, and
Endoskeletons
Hydrostatic Skeletons
Consists of fluid held under pressure in a closed body compartment– Cnidarians, flatworms,
nematods, and annelids These animals are able
to change shape because of the fluid-filled compartments– Flexibility– Ex. Worms.
Exoskeletons
This type of skeleton is a hard encasement deposited on the surface of the animal.
Ex. Molluscs Arthropods have cuticle
exoskeletons, a non-living coat. The cuticle contains chitin (polysaccharide similar to cellulose).
Endoskeleton
Consists of hard supporting elements, like bones.– Buried within the soft
tissues of an animal.
Echinoderms have endoskeletons of hard plates called ossicles beneath their skin.– Sea urchins vs. Sea
Stars
Joints
IB specifically wants you to know the human elbow joint. (11.2.2)
Specifically the cartilage, synovial fluid, joint capsule, named bones, and antagonistic muscles. – Make sure you can label
these things !!
Elbow Joint Continued
IB also wants you to know the functions of the structures in the human elbow joint (11.2.3)
Cartilage– A type of connective tissue with an abundance of collagenous fibers
embedded in chondroitin sulfate.– Cartilage is retained in certain locations
• Disks that acts of cushions between vertebrae and the caps on the ends of some bones
• Absorbs physical impact Synovial Fluid
– Thick stringy fluid found in the cavities of Synovial joints.– Reduces friction between the cartilage and other tissues in joints
Joint Capsule (Articular Capsule)– Envelope surrounding the Synovial joint– Covers the end surfaces of bones
Joints Continued
Three types of joints: Ball-and-socket joint
– Where the Humerus contacts the shoulder girdle, and our femur contacts the pelvic girdle
Hinge Joint– Between the Humerus and the head of the Ulna
Pivot Joint– Same place above
The Hip Joint and Knee Joint
IB wants you to know the comparison between the knee joint and the hip joint (11.2.4)
Knee Joint– Hinge joint, and is the biggest joint in our body
Hip Joint– Ball-and-socket type of joint, specifically called a
synovial joint.
Muscles
The purpose of muscles is to provide movement to the body by the providing ability to move bones. (11.2.1. IB wants you to know the purpose of muscles)
The action of a muscle is to contract– Muscles only extend passively
Antagonistic pairs, each member of the pair working against each other.– Ex. Flexing an arm
Vertebrate Skeletal Muscle
The skeletal muscle Structure (11.2.5 IB
wants you to know the skeletal muscle structure and its components)– Hierarchy of smaller and
smaller units– A muscle fiber = bundle of
smaller myofibrils– Myofibrils = two types of
myofilaments (thin filaments and thick filaments)
Structure Continued
Thin filaments– Two strands of actin and one
strand of regulatory protein Thick filaments
– Staggered arrays of myosin molecules
The arrangement of myofilaments make a pattern of light and dark bands. Each repeating unit is called a sarcomere.
There are two bands– I Band: area near the edge of
sarcomere where there are only thin filaments
– A Band: broad region that corresponds to the length of the thick filaments
• There is an H zone, which is in the center of the sarcomere
The Structure of the Sarcomere
Things to note (11.2.6)– Z lines– Light band– Dark band– H zone
Sliding-Filament Model
When the muscle contracts, thin and thick filaments do not change in length when the sarcomere shortens
There is an overlap between both filaments instead. – Results in the I band and
the H zone shrinking
Sliding-Filament Model Continued The sliding/overlap of the filaments
result from Myosin-Actin interactions Take a look at the diagram
Myosin-Act Interaction (11.2.7. IB wants you to know
how this works…so pay attention)
Role of Calcium and Regulatory Proteins Skeletal fiber only contracts when
activated by a motor neuron. This is where the Calcium and
Regulatory Proteins come into work
Role of Calcium and Regulatory Proteins (11.2.7)
The Stimulus
The stimulation provided by the motor neuron is an action potential that makes a synapse with the muscle fiber.
The synaptic terminal releases neurotransmitters, called acetylcholine– Depolarization, causes it to produce action potential
The action potential spreads into …– A plasma membrane called transverse (T) tubules– And then the sarcoplasmic reticulum (SR) which the
tubes make close contact with• The action potential opens Calcium ion channels in
the SR• (look at diagram on pg. 1070)
A quick look at the standards..
11.2.1: State the roles of bones, muscles, etc in human movement
11.2.2: Label a diagram of the human elbow joint, including cartilage, synovial fluid, joint capsule…etc.
11.2.3: Outline the functions of the structures in the human elbow joint named in 11.2.2
11.2.4: Compare the movements of the hip joint and knee joint 11.2.5: Describe the structure of striated muscle fibers, including
myofibrils with light and dark bands… etc 11.2.6: Draw and label a diagram to show the sarcomere,
including Z lines, actin filaments, myosin..etc 11.2.7: Explain how skeletal muscle contracts, including the
release of calcium ions from the SR, formation of cross bridges…etc.