Support and Locomotion Support and Locomotion Organisms that

Support and Locomotion

Support and Locomotion Organisms that are capable locomotion are Motile, Those that don’t move much are Sessile

What are some advantages of Locomotion? – – – Getting Food Find places to live Move away from harmful conditions Escape enemies Find shelter Mating and Reproduction

Need for support: Skeletons • Some are made of hard material, others are soft. : Calcium compounds, chitin. • Muscles are attached to it. • Types: – Hydrostatic – Endoskeleton – Exoskeleton

Types of Skeletons 1. Hydrostatic Skeleton: -Fluid held under pressure in closed body compartment. • i. e. : hydra, earthworm How does this provide support? 1. Protects body parts 2. Gives body its shape 3. Provides support for muscle action What are its limitations? 1. 2. Motility posture

Hydrostatic Skeletons Protist Locomotion • Motile Protists use: – pseudopods – Cilia – flagella

Locomotion 1. Pseudopod • temporary projections of the cell surfaces. • Cytoplasm flows into and out of the pseudopod. • Only occurs on solid surfaces.

Ex: Ameoba Locomotion • Cytoplasm is in two states – Endoplasm – center of cell, more fluid – Ectoplasm - fluid moves into pseudopod and spreads out becoming less fluid – Ectoplasm moves to back of cell and becomes endoplasm again

• 2. Cilia – Hair-like structures (thousands) that move in rhythmic beating movements that move an organism through water. (Paramecium)

• 3. Flagella – Like cilia but longer – Usually only 1 or 2 per cell – Whip-like movements propel cell through water. (Euglena)

Hydra Locomotion 1. 2. 3. 4. 5. Contractile fibers – move in several ways Mucus secreting cells & amoeboid cells – glide along its base Somersaulting Inch along attaching its tentacles and pulling itself Float upside down by making an air bubble in its base

Earthworm Locomotion • Two layers of muscles: – Outer Circular layer – Inner Longitudinal Muscles • When circular muscles contract, the worm gets longer, when the longitudinal muscles contract the worm gets shorter • Fluid inside worm stiffens when muscles contract, allow it to push through soil • Setae: four pairs of bristles on each segment; act as anchor

How does this happen? 1. 2. 3. 4. 5. Setae in rear hook into ground Circular muscles contract and fluid stiffens Earthworm lengthens and pushes through soil Setae in front of worm anchor into soil, setae in the rear relax and un -anchor. Longitudinal muscles contract, shortening the body and pulling the backend forward

Types of Skeletons 2. Exoskeleton: - skeleton is on the outside of the body. ( clams, crabs, lobster, oysters) • Crabs, insects: exoskeleton made of chitin - Protection - Can not grow.

Exoskeletons Grasshopper • Exoskeleton composed of chitin • Divided into plates, separated by joints • Walk, jump, fly. • Body has three divisions: – head – thorax – abdomen

Grasshopper Exoskeleton • Thorax: • 3 pairs jointed legs • First 2: walking • Hind pair: jumping • 2 pairs wings • Outer pair protects inner pair (flying) – Muscles work in pairs

Exoskeletons • Cicada’s shed exoskeleton

Types of Skeletons 3. Endoskeleton – Skeleton found inside the body – Made of bone and cartilage (connective tissue) – Does not protect like an exoskeleton. – Skull: brain, Rib cage: organs – Grows – Fish, amphibians, reptiles, birds, mammals

Human Musculoskeletal System • Endoskeleton • Bones – Type of connective tissue – Hard and inflexible – Muscles attachment site – serve as levers – Support – Protection – Storage for minerals (calcium, phosphorus) – Produce Red and White blood cells

Components of Bone 1. Osteoblasts • Bone makers • Secrete collagen and minerals • Osteogenesis Collagen – strong protein material – fibers tied together by polysaccharides to form cement Calcium and phosphate Ions gives bones hardness and heaviness 4. Osteocytes • Mature bone forming cells 5. Osteoclasts • Bone remodelers

(Components continued) 6. Haversian Canals Cavity containing blood vessels and nerves. 7. Periosteum • tough membrane on outside of bones (except at ends). • makes new bone for growth and repair. • where muscles are attached, • contains blood vessels and nerves.

8. Marrow Red marrow • makes RBC, platelets and WBC • in spongy bone of long bones, vertebrae, ribs, breastbone, cranium Yellow marrow • made of fat cells • in hollow center of long bones

Types of Bone • Compact bone – very dense, strong • Spongy bone – more porous • Most bones contain both types of tissue

Human Skeleton • Contain 206 bones • Two parts: – Axial skeleton • • Skull Vertebrae Ribs Breastbone – Appendicular skeleton • • Arm bones Leg bones Pectoral girdle Pelvic girdle

Joints • Joints are where bones meet bones • Types: – Immovable Joints – Hinge Joints

Types of Joints – Ball & Socket Joints – Pivot Joints – Gliding Joints

Supportive Structures • 1. Cartilage – type of connective tissue – Bends easily – Joint lubrication – Absorbs force – cushions against impact or pressure – Gives support while allowing motion

How do you stabilize those joints?

Supportive Structures 2. Ligaments – Tough connective tissue – Attach bones to bones 3. Muscles – Attached to bones – Pull on bones when contracted

Supportive Structures 4. Tendons • connect muscles to bone

Changes in Development – In embryo, skeleton is cartilage then changes to bone (ossification) – Bones of small children are more cartilage than bone – In adults, found on ends of bones, nose, ears

Muscles • Muscle Types: – Skeletal muscles • Striated • Used in locomotion and in voluntary movement • muscle fibers – group of cells fused together • Bundles of muscle fibers bound by connective tissue

Muscles • Smooth Muscle • • Involuntary Regulated by nerves and hormones unstriated Found in: – Walls of digestive organs – Walls of arteries and veins – Diaphragm

Muscles • Cardiac Muscle – Involuntary and striated – In heart – Regulated by nerves and hormones

Muscle components • Muscle Fibers – Are innervated by nerve impulse. – A motor unit is a nerve and the muscle fiber it stimulates. – Consist of myofibrils • Myosin protein filaments – thick filament (dark) • Actin filament – thin filament (light)

Components • Sarcomere: contractile unit • Many sarcomeres are in a myofibril • Actin and myosin are in a sarcomere

How does a muscle contract?

Sliding Filament Theory • Muscle fibers shorten when actin slides over myosin • Energy for sliding is by ATP

Take another look

How do muscles work? • Muscles pull when they contract • Work in Antagonistic Pairs – Biceps flex the elbow – Triceps extend the elbow • Muscle Tone – When you are conscious, your muscles are never completely relaxed. Muscles are “ready”. – Responsible for posture