Daniel Goss - Concept 2 Notes - Lymphatic System PDF

 Overview Joints (articulations) = the meeting places between 2 or more bones – They give the skeleton mobility and hold it together Body movements happen when muscles contract across joints, moving one bone toward another Important connective tissues: – Ligam...

 Overview Joints (articulations) = the meeting places between 2 or more bones – They give the skeleton mobility and hold it together Body movements happen when muscles contract across joints, moving one bone toward another Important connective tissues: – Ligaments: attach bones to bones – Tendons: attach muscles to bones Joints can be classified by structure or function  Functional Classification Based on what they do and how much movement they allow – Note: The less movable the joint, the more stable it is 3 Types: – Synarthroses = Non-moving joints Ex. The part of the skull that protects the brain = cranium – Amphiarthroses = Slightly-moving joints Ex. Where pubic bones meet in the pelvis – Diarthroses = Freely moving joints Ex. Like knee and elbow joints, mainly in our limbs  Structural Classification Based on what binds the bones together in the joint and if a cavity is present 3 Types: – Fibrous joints = connect bones with the collagen fibers of dense connective tissue Mostly immovable - Ex. Bones in the skull are held together = fibrous joints called sutures - Ex. Fibula and tibia in your lower leg are held together by ligaments only = fibrous joints called syndesmoses - Ex. The way teeth are embedded in their sockets = fibrous joints called gomphoses  Structural Classification 3 Types: – Cartilaginous joints = connect bones with cartilage Can be rigid but also slightly movable – Ex. An immovable joint made of a bar/plate of hyaline cartilage between the sternum and the first rib = synchondrosis – Ex. A slightly movable joint made of fibrocartilaginous intervertebral discs that act as a shock absorbers between vertebrae = symphysis  Structural Classification 3 Types: – Synovial joints = connect bones with dense connective tissues AND a fluid filled joint cavity Allows them to be freely movable (all are diarthroses)  Synovial Joints 6 Special Features: – Articular cartilage that covers the opposing bone surfaces – Joint (articular) cavity – A fibrous joint (articular) capsule that encloses the cavity  Synovial Joints 6 Special Features: – Synovial fluid in the cavity that acts as a lubricant – Bandlike ligaments for reinforcement – Sensory nerve fibers and blood vessels (in the joint capsule and synovial membrane) 6 types of configurations: gliding, hinge, pivot, condylar, saddle, and ball and socket  Gliding Also known as a “plane” joint Allow gliding movements = When one flat bone surface glides or slips over another (back and forth or side to side) Ex. Intercarpal joints (in wrist) and intertarsal joints (in ankle)  Hinge Only moves in one direction (like a door hinge!) Allow angular movements like flexion and extension – Flexion: bending in a way that decreases the angle of the joint so the articulating bones get closer – Extension: reverse of flexion Hyperextension: going beyond the anatomical position Ex. Elbow and interphalangeal (finger) joints  Pivot Allow rotation as well as twisting movements back and forth – Supination = turn/twist forward – Pronation = turn/twist backward Ex. Where humerus meets radius and ulna at the elbow  Condylar Like a pedestal with a joint on top Allows movements like flexion/extension, as well as abduction and adduction – Abduction: “moving away”; moving a limb away from the median plane, along the frontal plane – Adduction: “moving toward”; opposite of abduction Ex. In the wrist  Saddle Allows opposition movements as well as flexion/extension, abduction/adduction Ex. Thumb joints  Ball and Socket Lots of maneuverability Allow rotational movements, abduction/adduction, flexion/extension – Rotation: turning of the bone around its own long axis Ex. Shoulder and hip joints  Other Types of Movements at different joints Circumduction: moving limb in a circle; Ex. Making circles with arms Elevation and depression: lifting (then lowering) a body part superiorly; Ex. Shrugging your shoulders, jaw dropping Protraction and retraction: Ex. Sticking jaw out (to make an under bite) and back in Dorsiflexion and plantar flexion: Lifting foot up and down at the ankle Inversion and eversion: Turning the foot towards the midline of the body vs. turning away from the midline of the body  Muscle Contractions Bones can’t move without the joints that connect them and the muscles that stretch over those joints Movement occurs when muscles contract – They always pull, never push 2 main types of contractions: – Isotonic = causes a change in the length of the muscles Ex. Lifting a box or doing push-ups – Isometric = no change in length Ex. Standing with good posture or doing a plank  Muscle Contractions Insertion = the movable bone during a muscle contraction Origin = the bone that moves less or not at all – Ex. In a bicep curl, the radius is the insertion point and pulls towards the scapula, which is the origin  Overview The integumentary system = your skin and all its accessories/appendages (glands, hair, and nails) Main function = protection Other functions = – Synthesizing vitamin D – Regulating body temperature – Balancing bodily fluids – Sensations 🡪 processing environmental stimuli – Excretion  Structure of Skin Main Layers: Epidermis – Made of epithelial tissue – Gets all its nutrients from the dermis Dermis – Made of mostly dense connective tissue – Majority of our skin 🡪 this is where the work gets done! – Embedded with blood vessels, glands, hair Blood follicles, and nerves vessels  Epidermis Dead keratinocy te Made of 4 types of epidermal cells: Dendritic – Keratinocytes: produce keratin (a protective protein) (Langerhans) cell – Melanocytes: produce Keratinocy melanin (a pigment that protects the nucleus of te keratinocytes from UV radiation damage) Tactile epithelial (Merkel) cell Melanocyt Melani – Dendritic (Langerhans) cells: ingest foreign invaders and e n activate the immune system – Tactile epithelial (Merkel) cells: sit where the epidermis and dermis meet and combine with nerve endings to make sensory receptors for touch  Stratum Stratum Epidermis Made of 4-5 layers: granulosu corneu m Dead keratinocy te – Stratum corneum: (horny layer) 20-30 m layers of dead cells bound tightly together to Dendritic (Langerhans) prevent water loss and cell protect layers below it spinosum Stratum Keratinocy – Stratum lucidum: (clear te layer) not pictured, only in “thick skin”; a thin Tactile band of flat, dead basale keratinocytes just below Stratu epithelial m (Merkel) cell Melanocyt Melani the stratum corneum e n – Stratum spinosum: (prickly/spinous layer) – Stratum granulosum: contain intermediate filaments that resist tension; (granular layer) 1-5 dendritic cells are most abundant in this layer layers of cells; where – Stratum basale: (basal layer) a single row of cells fill with keratin; stem cells attached to the dermis where most tough and water- new cells are made resistant  Dermis 2 Layers: – Papillary dermis: made of areolar connective tissue, interwoven loosely with collagen, elastic fibers and blood vessels Dermal papillae = projections from its surface into the epidermis that contain capillary loops, nerve endings, and touch receptors – Reticular dermis: made of dense irregular connective tissue and houses a network of blood vessels and thick bundles of collagen fibers that give the dermis strength and resiliency  Structure of Skin Main Layers: Hypodermis – Aka subcutaneous tissue – Technically not part of the skin – Mainly made of adipose tissue (fat) – Functions: Insulation against heat loss Energy storage Shock absorber Anchors skin to underlying structures (mostly muscles)  Skin Appendages Hair Hair = long filaments Arrector pili Hair made of dead shaft keratinocytes Hair root Hair – Made of 3 layers: bulb in follicle Medulla = central core made of soft keratin Cortex = bulky layer Root Dermal hair papilla Cuticle = single layer of overlapping cells, like plexus shingles on a roof – When the cuticle wears away at the tip of the hair shaft it causes split ends  Skin Appendages Hair follicles Hair follicles = tubular invaginations in the epidermis that hair grows out of – Deep end of root = hair bulb – Arrector pili = smooth muscle cell bundle that contracts to raise hair upright Dermal – Root hair plexus (hair follicle papilla receptor) nerve fiber endings that perceive touch and wrap around each bulb – Dermal papilla has capillaries that supply hair with nutrients and signal growth  Skin Appendages Hair follicles The shape of the hair follicle plays a major role in the texture of your hair – The flatter the follicle, the curlier the hair will be Straight Wavy Curly  Appendages Nails Made of heavily keratinized cells 3 parts = root (embedded in skin), plate/body, and free edge (what you trim) Rests on part of epidermis called the nail bed Nail matrix = where nail grows  Appendages Sebaceou s gland Sweat pore Glands Our skin has sweat glands, that Eccrine sweat mainly work to keep us from gland overheating, and sebaceous (oil) Apocrine glands, that mainly work to sweat gland prevent water loss. Two types of sweat glands: – Eccrine sweat glands: most abundant; extra in palms, forehead, and soles of feet – Apocrine sweat glands: lie deeper in dermis and are larger; come in during puberty and empty into the hair follicles around the armpits and groin 2 types of modified apocrine glands = ceruminous glands in the ear canal that make ear wax, and mammary glands that secrete milk  Appendages Glands Sweat pore Sweat Sebaceous gland gland  Appendages Glands Eccrine Apocrine Sebaceous sweat glands sweat glands glands Temperature control Unknown; Lubricate/soften skin and antibacterial Potentially sexual & hair, slow water Function(s) properties scent glands loss, and antibacterial properties Type of Sweat + proteins Sebum (an oily Sweat secretion and fatty substances secretion) Where Usually upper part Usually upper part of hair follicle, secretion Surface of the skin of hair follicle, rarely sometimes skin exits skin surface surface Everywhere, but Axillary and Everywhere Where in extra in palms, anogenital regions EXCEPT palms and the body soles, and forehead of the body soles  Functions Protection 🡪 creates the following barriers: – Physical: from its many layers of cells and its continuity – Chemical: skin secretes natural antibiotics (defensins) and most secretions have a low pH, both for killing bacteria Melanin = a chemical pigment shield to protect against UV damage; made by melanocytes – Biological: immune cells Dendritic cells in the epidermis patrol beneath the surface to capture invaders 🡪 immune response Macrophages in the dermis act as a 2nd line of defense 🡪 an immune response if invaders make it through the epidermis  Overview Function = return fluids that have leaked from the vascular system back to the blood – Helps to maintain blood volume levels, and thus blood pressure Main structures = lymphatic vessels, lymph, and lymph nodes – In the picture, the red shows oxygenated blood being pumped from lungs 🡪 heart 🡪 rest of the body via arteries. – The blue shows deoxygenated blood returning from the body via veins 🡪 heart 🡪 lungs. – The green shows the lymphatic vessels that are intertwined throughout the capillary beds and sending lymph 🡪 heart.  Overview Main structures = lymphatic vessels, lymph, and lymph nodes – Lymphatic vessels = networks of drainage vessels that collect and return excess interstitial (tissue) fluid to the blood – Lymph = the protein-containing fluid that moves through lymphatic vessels – Lymph nodes = small organs that act as checkpoints to filter the lymph as it moves through the body Contains immune cells (macrophages and lymphocytes) Lymphoid organs (spleen, thymus, tonsils) and tissues are key structures of the immune system  Lymphatic Vessels Form a one way system – Lymph only flows towards the heart – Begins in microscopic lymphatic capillaries, interwoven between tissue cells and blood capillaries Structure makes them more permeable than blood capillaries, so they can easily take in large particles (like proteins, cell debris, pathogens, and cancer cells)  Lymphatic Vessels Lymph moves from lymphatic capillaries 🡪 collecting lymphatic vessels 🡪 lymph nodes 🡪 lymphatic trunk 🡪 lymphatic duct 🡪 the heart – Collecting lymphatic vessels: similar to blood vessels – Lymph nodes: where lymph gets filtered – Lymphatic trunks: where lymphatic vessels unite and drain large areas of the body – Lymphatic ducts: Right lymphatic duct takes lymph from right upper limb, right side of head, and thorax to the heart via the internal jugular vein Thoracic duct takes lymph from everywhere else to the heart via the subclavian vein  Lymphatic Vessels By returning this excess fluid to the heart, the lymphatic vessels also: – Return leaked proteins to the blood – Carry pathogens and cancer cells to the lymph nodes – Carry absorbed fat from the intestines to the blood Via specialized lymphatic capillaries called lacteals  Lymphoid Cells Make up lymphoid tissues which make up lymphoid organs Lymphoid cells are mainly immune system cells – Lymphocytes = main warriors of the immune system T Cells: directly attack invading substances and manage the immune system B Cells: secrete antibodies into the blood – Macrophages = phagocytize (“eat”) foreign substances and activate T cells Lymphoid cells also include: – Reticular cells = produces a fiber called stroma that creates a network to support the other cells in lymphoid organs and tissues  Lymphoid Organs Two Functional Groups: – Primary lymphoid organs: Red bone marrow and the Tonsils and thymus adenoid B Cells are made and mature in s Red Thymu the red bone marrow s bone T Cells are made in the red marro Lymph w bone marrow and mature in the nodes thymus – Secondary lymphoid organs: lymph nodes, Splee spleen, and mucosa- Peyer’s n associated lymphoid tissue patches (MALT, which includes theAppendi Lymph tonsils, Peyer’s patches, x nodes and the appendix) Where mature lymphocytes are activated  Lymphoid Organs PRIMA RY Thymus Function: Where T cells mature so that they can actually defend us against pathogens when activated in an immune response – Key role early in life  Lymphoid Organs SECONDAR Y Lymph Nodes Located along the lymphatic vessels throughout the body Efferent Afferent Capsul lymphati lymphati e Functions: cleanses c vessel c vessel lymph and activates the immune system – Most important because it is the only one that actually cleanses the lymph Dendritic cells bring antigens to lymph nodes Macrophages destroy pathogens and debris so they aren’t delivered to the blood Corte and then spread elsewhere x Medull  Lymphoid Organs SECONDAR Y Spleen Functions: Spleen Cleanses blood and removes aged/defective RBCs, debris, and foreign substances in the red pulp tissue – These broken down RBCs get recycled and stored (such as salvaged iron, blood platelets, and monocytes - a type of WBC) Activates and proliferates lymphocytes in the white pulp tissue  Lymphoid Organs SECONDAR Y MALT Mucosa-associated lymphoid Tonsils tissue (MALT) = set of lymphoid and tissues located in mucous adenoid s membranes throughout the body Functions: – Prevent pathogens from penetrating mucous membrane – Site of lymphocyte Peyer’s patches activation and proliferation Appendi Includes: tonsils, Peyer’s x patches, and the appendix  Lymphoid Organs SECONDAR Y MALT Tonsils = a ring of MALT around the entrance of the pharynx that gathers and tries to remove any pathogens from food or inhaled air before they can enter the GI tract or lungs Norm Inflame al d Tonsil Tonsils s  Lymphoid Organs SECONDAR Y MALT Peyer’s patches = clusters of lymphoid tissue in the ileum of the small intestine that monitor intestinal bacteria populations and prevent the growth of pathogenic bacteria Ileu m  Lymphoid Organs SECONDAR Y MALT Appendix = contains a bunch of lymphoid tissue to prevent bacteria from breaching the intestinal wall and generating “memory” lymphocytes for establishing long-term immunity  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  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  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. Long bones 2. Short bones 3. Flat bones 4. 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  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  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  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