Module 1: Levels of Organization
Chemical Level
- everything in the universe is made up of matter
- all matter is composed of substances called elements
- atom: single particle of an element
- molecule: two or more atoms chemically bonded
- compound: two or more molecules bonded together
Organic (Carbon containing) Carbohydrates (energy) Lipids (fats, hormones) Proteins (structure, hormones, enzymes, antibodies, etc.) Nucleic acids (DNA)
| Inorganic (No carbon) Water Salts (electrolytes) Acids bases
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Cell Level
- cell: basic unit of structure and function
- nearly 100 trillion cells in the average adult can be classfiied into 200 different cell types
- size and shape of cells vary
- cell’s size and shape is directly related to its function in the body
Tissue Level
- tissue: cluster of connected cells with similar function
- histology: the study of the microscopic structure of tissues
- Four basic types of human tissues:
1. Epithelial Tissue
2. Connective tissue
3. Muscle Tissue
4. Nervous Tissue
Epithelial Tissue: made up of cells that line the inner and outer body surfaces to protect the body and its internal organs, and secrete and absorb substances
Ex: skin, lining of digestive tract
Classified based on cell shape and arrangement (layers)
Cell shapes: Squamous (flat Cubodial Columnar
Arrangement: Simple: single layer, thin, good for secretion, absorbtion and filtration, not good for protection Stratified: more than 1 layer, durable, good for protection
| Connective tissue: made up of cells that form the body’s structure
Ex: bone, cartilage, adipose (fat)
Cassified as either Dense of Loose Dense Connective Tissue: matrix of collagen fibers with fibroblasts (fiber-forming cells) that form strong, rope-like tissue Loose Connective Tissue: softer, more cells, less fibers Areolar tissue: most widely distributed connective tissue, wraps aroudn organs holding them in place and providing protection Adipose tissue: commonly called fat tissue, insulation/protection Reticular tissue: delicate framework of reticular fibers that create internal framework to support freely moving cells (like blood cells)
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Muscle tissue: made up of cells tha thave the unique ability to contract, or become shorter. Muscles attached to bones enable the body to move | Nervous Tissue: mad eup of neurons, or nerve cells, that carry electrical messages. Nervous tissue makes up the braina nd the nerves that connect the brain to all parts of the body |
Organ Level
- Organs: structures that conssit of two of more types of tissues that work together to do the same job
Organ Systems
- Organ systems: groups of organs that work together to carry out a complex overall function. Each organ of the system does part of the larger job
Organ System | Organs | Function |
Integumentary system | | Protect the tissue beneath them |
Muscular system | Cardiac muscle Smooth muscle Skeletal msucle
| Work with the skeletal system to help you move |
Cardiovascular system | Heart Arteries Veins Capillaries blood
| Pump blood through all the vessels of your body |
Respiratory system | Noes Pharynx Larynx Trachea Bronchus Lung Diaphram
| Take in oxygen, remove carbon dioide |
Nervous system (CNS and PNS) | Brain Spinal cord Nerves Motor neurons Sensory neurons Somatic Nervous System Autonomic nervous system
| Receives and sends electrical messages throughout the ody |
Digestive System | Teeth Mouth Salivary glands Pharynx Esophagus Stomach Liver Gallbaldder Pancreas Small intesitne Large intestine Rectum Anus
| Breaks down food so it can be used by the body |
Urinary system | Kidney Ureter Urinary bladder urethra
| Produce, sotre, and eliminate urine |
Lymphatic System | Tonsils Thymus Spllen Lymph nodes Lymphatic vessels
| Returns leaked fluids to blood vessels, and helps get rid of bacteria nad viruses |
Endocrine system | Pituitary galnd parathyroid gland thryroid gland thymus gland adrenal gland Pancreas Ovaries testes
| Controls functions by using chemicals made by the endocrine system |
Reproductive System | Female Ovary Fallopian tube Pubic bone Uterus Urinary bladder Urethra Vagina
Male Vas deferens Urinary bladder Urethra Pubic bond Prostate gland Epididymis Penis Testes scrotum
| Female: produce egg, nourshies and protects the fetus Male: produces and delivers sperm |
Skeletal System | Bones Joints Ligaments cartilage
| A frame to protect and support your body parts, produce blood cells, storage of minerals |
Metabolism: the sum of all the chemical processes that occur int he body Catabolism: breakdown of complex chemical substances into simpler components (ex: digestion of proteins in food to amino acids) Anabolism: the building up of complex chemical substances from simpler components (Ex: amino acdis being used to build new proteins that form muslces and bones)
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Movement: includes the motion of the whole body, individual organs, single cells,a nd even tiny structures inside cells Ex: the coordinated movement of your leg msucles to move your whole body when you walk/run Ex: the movement of white blood cells into an infected or damaged tissue to clean up or repair the area
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Growth: an increase in body size that results form an increase int he size of existing cells, and increase in the number of cells, or both |
Differnetiation: the development of a cell form an unspeciialized state to a specialized state |
Reproduction: the formation of new cells for tissue growth, repair, or replacmdent (meiosis) |
Negative Feedback Loop More common Counteracts change, returnign to homeostasis Ex: body temeprature, glucose levels
| Positive Feedback loop: Less common Amplify changes, moving away from homeostasis Ex: fever, contractiosn during childbirth
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Set point range: normal range the body tries to stay within |
Stimulus: an imbalance in homeostasis outside the set point range |
Sensor: monitors the change and sends “input” to the control center |
Control: processes “input” and releases “output” |
Effector: receives the “output” and produces the repsonse |
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Anatomical Position Standing upright Facing the observer Head level, eyes forward Feet flat, directed forward Arms at side, palms forward
| Body positions: Prone- lying face down Supine - lying face up |
Regional names: Head = skull and face Neck = supports the head and attaches it to the trunk Trunk = chest, abdomen, & pelvis Upper limbs = shoulders & arms Lower limbs = buttocks, thighs and legs
| Body cavities: spaces within he bdoyt hat help protect, separate, and support internal organs Cranial cavity Vertebral cavity Thoracic cavity Adominal cavity Pelvic cavity
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Directional Terms: Superior Above vs. Inferior - below Posterior (Dorsal) - towards back vs. Anterior (ventral) - towards front Medial - towards center vs. lateral - away from center Proximal - closer to the trunk vs. Distal- further from the trunk
| Anatomical Planes: Frontal plane - divides the body into anterior and posterior Transverse plane - divides the body into superior and inferior Sagittal - difvides the body into right and left
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Cranial and Vertebral Cavities
Formed by the skill and vertebrae of the spine
Cotnaint he braina nd spinal cord
Lined with layers of protectice tissue called meninges
* meningitis: dangeorus swelling of meninges caused by bacterial or viral infection
Thoracic Cavity
Pleural Cavities - cotnaint he lungs
Pericardial caivty - cotnaisn the heart
Mediastinum - cotnaisn the esophagus, trachea, thymus, and pericardial cavity
Daiphrahm - dome shaped msucle that separates the throacic and adominopelvic cavity
Abdominopelvic Cavty
Abdominal cavity - cotnaisn stomach, spleen,l liver, gallbladder, small intestine, and most of large intestine
Pelvic cavity - cotnaisn urinary bladder, part of large intestine and internal reproducitve organs
Module 2: Skeletal System
Functions
1. Support and structure
2. Protects internal organs
3. Provides attachment surfaces for msucles (Movement)
4. Produces blood cells (hematopoiesis)
5. Storage and mineral homeostasis
Support and structure: human body
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protection:
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Facilitates movement
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Hematopoiesis: process that produces red blood cells, white blood cells,a nd platelets
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Storage ad mineral homeostasis
Mineral homeostasis Bones store 99% of the body’s calcium Cotnributes to the strneght of bones Bones release minerals into the bloodstream to maintian critical mineral balances (homeostasis)
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Calcium Regulation Feedback Loop:
If calcium levels are too high:
If calcium levels are too low
Axial Skeleton | Appendicular Skeleton |
Axial Skeleton:
Bones: Occipital bone Temporal bones Parietal bones Frontal bone Sphenoid bone Ethmoid bone
Nasal bones Lacrimal bones Palatine bones Zygomatic bones Inferior nasal Concha Vomer Maxillae Mandible
Coronal (frontal) suture - betweenf rontal + parietal Saggital suture - between 2 parietal Lambdoid suture - between parietal + occipital Squamous suture - between pairital and temporal
Mastoid process - posterior of temporal, bone behind ear Styloid process - inferior temporal bone, attachement for severla msucles Mandiular congyle - where mandible articulates witht eh temporal bone Occipital condyle - (inferior view) where the skill articulates witht eh vertebrae External audiotry meatus (to Ear canal) Zygomatic arch (forms cheekbone)
Formaen magnum - large hole at the base f the skull where the spinal cord connects to the brain Carotid foramen - passage for the carotid artery (carries blood to the brain) Jugular foramen - passage for the jugular vein (carries blood away from the brain)
3 Audiotry ossciles in each middle ear Malleus (hammer) Incus (anvil) Stapes (stirrup) - smallest bone int he human body
Muscles and ligaments attach it to the skull Where some tongue muscles attach Elevates the larynx (voicebox) durign speech or swallowing
26 individual bones 7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae 1 sacrum 1 coccyx (tailbone)
Body: weight bearing protion of the vertebrae, separated by intervertebral disks Arch: forms the vertebral foramen, where the sinal cord is located Processes: projection or outgrowth of tissue, vary based ont he type of vertebrae
Atlas (C1): holds the head, “Yes” motion, tilt head side to side Axis (C2): rotation around the dens, “no” motion
Large, thick bodies to carry a large amoutn of weigth Most common area for ruptured intervertebral disks
Funtions: protection of vital organs within the thorax, prevents collapse of thorax during repsriation Consists of: thoracic vertebrae, ribs, sternum
Ribs: 12 pairs of ribs True ribs (1-7): attach directly to the sternum by carilage False ribs (8-12): do not attach directly to sternum by cartilage “Floating ribs” (11 &12): do not attach to the sternum at all
Sternum: 3 parts Manubrium (handle) Body (sword blade) Xiphoid (sword tip)
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Appendicular Skeleton
Humerus Radius Ulna Carpals (wrist) Metacarpals (hand) Phalanges (fingers)
Femur Tibia Fibula Tarsals (ankle) Metatarsals (foot) Phalanges (toes)
Pectoral (Shoulder Girdle: attaches the bones of the upper limb to the axial skeleton Clavicle (collarbone)- “S” shaped boned that connects to the scapula and sternum, creates the anterior portion of the pectroal girdle Scapula (shoulder blade) - flat bone that protects organs and serves as an attachment for msucles, creates the posterior of the pectoral girdle
Humerus: Longest bone of the upper limb Connects proximally witht eh scapula, and distally witht he ulna and radius Called the “funny bone”
Ulna and Radius: Longer Medial (pinky side)
Carpals - 8 in each wrist, each wth unique shapes and names Metacarpals - 5 bonds of the hand, numbered 1-5 beginning at thumb Phalanges - 3 in each finger (except for thumb), proximal, middle, and distal, 14 per hand
Pelvic (Hip) Girdle: 3 components Ilium
Ischium
pubis
Femur: Thigh bone Longest, heaviest, strongest bone in the body Connects proximally with the hip bone,and distally with the tibia and patella
Patella: Kneecap Small triangular bond Protects the knee joint
Tibia and Fibula: two bones that make up the lower leg Shin bone Large, medial weight-bearing
Tarsals: 7 in each ankle, the largest of which forms the heel and is named Calcaneus Metatarsals: 5 in each foot, numbered 1-5 beginning with the big toe Phalanges: 3 in each tow (except big toe) proximal, middle, and distal
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Long bones: Longer than they are wide Typicaly joints on either side Attachment sites of msucles that move the body Ex: femur (thigh bone) Ex: phalanges (finger bones)
| Short Bones: As long as they are wide Provide stability Can easily glide over one another Ex: carpals (wrist bones) Ex: tarsals (ankle bones)
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Flat Bones: Thin and wide Surround and protect organs Broad surface for msucle atttachments Ex: scapula (shoulder balde) Ex: Cranium (skull)
| Irregular Bones: |
External Structures Diaphysis: bone shaft or body, main protion of the bone Epiphysis: enlarged area on either end of the bone Mataphysis: region between each epiphysis and the diaphysis Articular Cartilage: thin layer that covers the part of the epiphysis that forms an articulation (joint) with another bone reduces friction, absorbs shock Periosteum: layer of dense connective tissue that surrounds bone surface
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Internal Structures Medullary (Marrow) Cavity: hollow space withint he diaphysis (cotnaisn yellow marrow) Endosteum: thin membrane that lines the internal bone surface of medullary cavity Epiphyseal (Growth) Plate: within the metaphysis, where bone grows in length until age 18-21, when it is replaced by bone, elaving the epiphyseal line
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Compact Bone - Cortical Bone Strongest form of bone tissue found beneath the periosteum, provides protection and support Arranged into repeating sturctural units caled osteons (haversian system) Each osteon consists of a central (haversian) canal, which is concentrically arranged Lamellae - calcified rings Lacunae - small spaces in lamellae Ocetocytes - inside lacunae Canaliculi - small channels filled with extracellular fluid
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Spongy Bone Does not contain osteons, instead it consists of lamellae arranged in an irregular lattice called trabeculae Space created between trabeculae help make bones lighter and provide space for red bone marrow (location of hematopoiesis)
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Osteogenic Cell: unspecialized stem cells, only bone cells that divide, found in periosteum and endosteum | Osteocyte: mature bone cells, main cell in bone tissue |
Osteoblast: bone-building cells, become osteocytes | Osteoclast: bone-breaking cells, created form fusion of white blood cells, found in endosteum |
Ligaments: storng fibrous, connective tissue that ataches bones to other bones
Tendons: storng, fibrous connective tissues that attaches muscles to bones
Bone Growth
- ossification: the process by which bones form, occurs in 4 sitatuons
1. Initial formation
2. Growth
3. Remodeling
4. Repair
- ossification begins to occur at the 6th week of embyronic development
1. Intramembraous ossification (flat bones of the skull form this way)
2. Endochondral ossification (long bones for this way)
Growth: during infancy, childhood and adolescence
Growth in length (elongation) occurs at the Epiphyseal (Growth) plate Zone of resting cartilage: anchors epiphyseal plate to the epiphysis Zone of proliferating cartilage: cells here divide and secrete bone matrix Aone of hypertrophic cartilage: layer of large matruing cells, elongates diaphysis Zone of calcified cartialge: where osteoclasts dissolve calcified matrix, new bony matrix
Growth in Width (Appositional Growth) occurs in the periosteum and endosteum Periosteum: osteogenic cells differnetiae into osteoblasts, whcihs ecrete bone matrix and get trapped, becoming osteocytes and creating new compact bone tissue Endosteum: osteoclasts desotry bone tissue lining the medullary cavity, allowing the cavity to enlarge, ultimately increasing the bone thickness
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2 processes:
Phases of Bone Remodeling |
Activation - pre-osteoclasts are attracted to the remodeling sites and fuse to form multinucleated osteoclasts
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Resorption- osteoclasts dig out a cavity (resorption pit), releasing calcium
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Reversal- osteogenic cells (mesenchymal stem cells) appear along the pit where they proliferate (increase in number) and differentiate into osteoblasts
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Formation - mature osteoblast release osteoid, forming new matrix, which is mineralized with calcium and phosphate
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Quiescence - resting state, cells remain dormant until the next cycle
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Factors that affect Bone Growth and Remodeling |
Minerals - bone formationr equires a large amount of calcium and phosphorous, which can be obtained throug dietary intake
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Viatmins: vitamin A stimualtes osteoblast activity, Vitamin C is needed for collagen formation (matrix), Vitamin D increases absorption of calcium form the gastrointesitanl tract
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Hormones - during childhood, human growth hormones stimulate osteoblasts to prompt cell division at the epiphyseal plate, then at puberty, estorgens increase osteoblast activity resulting in “growth spurts” and the changeds in bone structures between genders
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Fracture - any break in a bone, named by severity, shape, or position of fracture line
Repair steps: fracture
Hematoma Formation: blood vessels crossign the fracture line ar ebroken, blood leaks and forms a clot, called a fracture hematoma (6-8 hours)
“soft callus” formation: a mass of soft cartilage bridges the broken ends of the bone creating a “soft callus”, or fibrocartilaginous callus (3 weeks)
Bony callus formation: osteogenic cells develop into osteoblasts, which begin to convert cartilage to spongy bone, creating a bony callus (3-4 months)
Bone remodeling: dead portions of the original bone are resorbed by osteoclasts, compact bone repalces spongy bone around outsid eof the bone
Bone tissue ahs the ability to alter its strength in repsonse to mechanical stress
When placed under stress, bone tissue becomes stornger due to increased osteoblast activity
Ex: bones of athletes, which are repetitively and highly stressed by exercise, become thicker and stronger than those of non-athletes
In the absence of stress, bone does not remodel normally because resorption happens more quickly than bone formation
Ex: astronauts, not experienceing the mechancial stress of gravity, experience bone loss of up to 1% per week
Aging:
Birth adolescence: more bone tissue is rpodcued than lost
Young adults: bone deposition and resportion are about equal
Beginning at middle age: bone resoption occurs more rapidly thanbone gain (due to decrease in hormones that acitvate osteoblasts) resulting in a loss of bone mass. Additionally, bones become more brittle (due to decrease in osteoid)
Bone dieseases and disorders
Ribular hemimelia
Rickets
Scoliosis
Module 3: Articulations
Cartilage, Ligaments and Tendons
- cartilage: tough, rubber-like tissue that covers an protects ends of bones
- ligaments = fibrous, connective tissue that holds bones to other bones
- tendons = another fibrous connective tissue that attaches muscles to bones
- joints provide structure/support, and allow for movement
- kinesiology = study of motion of the human body
Classification of articulations
Structure
- firbous joints
- Cartilaginous joints
- synovial joints
Function
- synarthrosis (immovable)
- amphiarthrosis (slightly movable)
- diarthrosis (movable)
Fibrous Joints | Articulating bones are held very closely together by strong connective tissue, allowing little to no movement
Ex: sutures |
Cartilaginous joints | Articulating bones are held together by cartilage, allowing for a slight amount of movement
Ex: symphyses |
Synovial joints | Unique joint that allows for free movement due to: Synovial cavity - space between bones filled with synovial fluid that lubricates and allows for a greater range of motion Articular capsule - surrounds the joint and cotnains the synovial cavity, connects to the periosteum Synovial membrane - inner layer of the articular capsule, contains fat for padding/absorb impact from motion
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Movement of synovial joints:
Gliding
Angular movements
Rotation
Special movements
gliding | Slimple movement in which relatively flat bone surfaces move back-and-forth and side-to-side No change in angle Limited range of motion
Ex: intercarpal movement |
Angular movement | Movement in whciht here is an increase or decrease in angle between bones
Flexion, extension Ex: nodding, bicep curls, kicking a soccer ball
Abduction, Adduction Ex: jumping jacks
Circumduction |
rotation | A bone revolves around its own longitudinal axis Ex: shaking head “no” |
Special movements | Only occur at certain joints Elevation = upward movement Depression = downward movement Ex: open/close mouth, shrugging Supination = turn palm anteriorly Pronation = turn palm posterioly Protraction = move body part anteriorly Retraction = move protracted body part back to anatomical position Plantar flexion = pointing toes Dorsiflexion = flexing foot |
Synovial Joint Types:
Planar joints
Hinge joints
Pivot joints
Condyloid joints
Saddle joitns
Ball-and-socket joints
Planar joints | Articulating surfaces are flat Ex: intercarapt joints (wrist) |
Hinge joint | Convex surface of one joint fits into concave surface of another Angular motion Flexion and extension
Ex: knee, elbow, fingers |
Pivot joint | Rounded or pointed part of one bone fits in a ring by another bone Ex: radioulnar joint |
Condyloid Joint | Oval shaped projection of one bone fits in an oval shaped depression in another bone Angular movement Flexion and extension Abduction and adduction
Ex: radius and wrist, knuckles |
Saddle joint | Saddle-shaped surface of one bone fits with other bone as a rider would sit Angular motion Flexion and extension Abduction and adduction Rotation movement
Ex: metacarpal and thumb |
Ball-and-socket joint | Ball like surface of one bone fits into a cup-like depression in anothe rbone Angualr movement Flexiona nd extension Abduction and adduction Rotation movement
Ex: hip and shoulder joint |
Range of motion
- range of motion (ROM): the full movement potential of a joint
- Goniometer: an isntrument for the precise measurement of angles
Prime Movers, Synergists, Antagonists - Skeletal Muscle
- prime movers: the muscle most responsible for the movement
- synergists: any movement is generally accomplished by more than one muscle. All of the muscles responsible for the movement are synergists.
- antagonists: muscles and muscle groups usually work in pairs, when one contracts the other relaxes
- fixator: stabilize a part of he body while other msucles ar emovign nearby
- movement: muscle moves bone by pulling, not pushing
Ex: the biceps flex your arm and its partner the triceps extend your arm. The two muscles are antagonist (cause opposite actions)
Module 4: Muscular System
Smooth muscle | |
Cardiac msucle | |
Skeletal msucle | |
Structure of Skeletal Muscle:
- most msucles attach 2 bones that have a movable joint between them
- origin: attachment to the bone that does not move
- insertion: attachment to the bone that moves
- tendons: dense connective tissue that anchors msucle firmly to bones
- ligaments: connect bone to bone
- blood and nerve fibers
- there are 640 skeleal muscles broken into groups based on:
Location (tibialis anterior) Shape (deltoid) Size (gluteus maximus) direction/orientation (rectus abdominis) Number or origins (Bicep, tricep) Place of attachment (Sternocleidomastoid) Action of the msucle (Extensor digitorum)
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Connective tissue
Vascualr tissue (blood)
Nerve tissue
Skeletal tissue
Connective tissue | Surrounds and protects muscular tissue Epimysium: outermost layer, surroinds entire muscle Perimysium: surrounds groups of 10-100 or more muscle fibers, separating into bundles called fascicles Endomysium: surrounds each individual muscle fiber (cell)
The epimysium, perimysium, and endomysium extend beyond the muscle fibers to help form the tendon |
nerve tissue | Somatic motor neurons: nerve cells that stimuluat skeletal msucle to contract |
Blood tissue | Veins and arteries: blood vessels that accompany each nerve in muscle |
M Line | |
H Zone | Around M line, only thick filaments |
Z Disc | Structure where new sacromeres start and end |
A Band | Composed of thick filaments, cotnaining myosin, form the darker stirpe seen in striation, anchored at the M line (middle of the sacromere) |
I band | Composed of thin filaments contianing actin form the lighter stripe seen in striation, extends into the A band, overlapping with thick filaments |
Fast twitch vs. Slow twitch
Twitch: refers to the contraction, or how quickly and often the muscle moves
Fast twitch: muscle fibers give you sudden brusts of energy but get tired quickly (strength athlete)
Slow twitch: muscle fibers are all about endurance or long-lasting energy
Muscle fiber anatomy (skeletal muscle)
sacrolemma | Membrane of the msucle fiber (muslce cell) |
T (transverse) Tubules | Tunnels front he sruface towards center |
Myofibril | Organelles of msycle cells that cotnract |
Sacroplasmic reticulum | Membrane that surrounds each myofibril, contains Ca+ |
filaments | Small structures within myofibrils, arranged in sacromeres |
Muscle Contraction
Neuromuscular junction
- a synaptic connection between the terminal end of a motor nerve and a muscle (skeletal/ smooth/ cardiac). It is the site for the transmission of action potential from nerve to the muscle
Excitation contraction coupling: the series of events that link the action potential (excitation) of the muscle cell membrane (the sarcolemma) to muscular contraction
Sliding Filament Theory: the sliding of actin past myosin generates muscle tension
Muscle growth and aging
- mature keletal msucle fibers cannot ungergo cell division
Growth after birth is due maintly to…
- hypertrophy: the enlargement of exisitng cells
- when muscles are exposed to stress, they experience microscopic damage. Cells fo the immue system repair this damage, resulting in a thickening of existing fibers
Factors that affect muscle growth:
Muscles and Aging
Exercise:
Low stress, endurance (aerobic): gradual transformation of some fast-twich fibers into slow-twich fibers, with slight increases ind diameter, number of mitochondria, blood supply, and strenght
High stress, short time (weight-lifting): increase in the size and strength of fast-twich fibers due to the increased diameter of thick and thin filaments, resulting in muscle enlargement
Muscle disorders/diesease
Module 5: Integumentary System
Organs:
Skin (integument, cutaneous membrane)
Hair
Nails
glands
Functions
1. Protection
2. Regulation
3. Sensation
Protection | Tightly interlocked cells of the skin protect underlying tissues from pathogens, abrasion, heat and chemicals Fats released inhibit evaporation of water, guarding agaisnt dehydration, and prevent excess absorption (shower) Release oils cotnaining bactericidal chemicals, kill surface bacteria Pigment helps sheild agaisnt damaging effects of UV light
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Regulation | Thermoregulation (body temp) Sweat glands: sweat produced, released to skin’s surface, and evaporates to reduce body temperature Blood vessels: 5% blood stored in skin, up to 25% typically circulating in skin Vasodilation: blood vessels widen, mor eblood flow, more heat lost Vasoconstriction: become narrower, less blood flow, less heat loss
Goosebumps: hair creates barrier → warmth Excretion and absorption Sweat excretion: excretes small amount sof salts, CO2, ammonia, and urea (from breakdown of proteins) Lipid soluble absorption: topical treatments (applied to skin), toxic substances (heavy metals, lead, arsenic, poison ivy, poison oak, viatmins A, D, E and K
Viamin D synthesis: requires UV light (10-15 minutes, at least twice a week) |
Sensations | Cutaneuous sensations: sensations that arise fromt he skin Tactile sensations Touch Pressure Vibration tickle
Thermal sensations pain |
Indication fo Homeostasis:
Cyanosis: (blye skin) heart failure, poor circualtion, severe respiratory issues
Jaundice: (yellow skin) liver disorder, or failure
Erythema: (red skin) fever, inflammation, allergy
Organization of the Integumentary System
Thin skin:
Thick Skin:
Epidermis
| Most superficial Protection Avascular, it does not contain any blood vessels Cells in the epdiermis must receive all their nutrients form the dermis below As the newer cells near the dermis dvidie, they push older cells towards the sruface, further from the nutrients of the dermis
5 zones/layers = strata Strata basale
Deepest layer, connects to dermis Single layer of karatinocytes Constantly undergoing cell division Millions of new cells daily
Stratum spinosum
Stratum granulosum
Stratum lucidum
3-5 layers of flattened, dead keratinocytes missing from thin skin only present in thick skin of palms, digits, and soles of feet
Stratum corneum
20-30 layers of dead keratinocytes Create durable barrier “Shed” and replaced by cells form below New epidermis every 25-45 days
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Dermis
| Largest, central Protection, regulation, and sensation Responsible for many of the fucntions of the integumentary system
Contains: 2 layers Papillary dermis
Reticular dermis
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Hypodermis (subcutaneous)
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Keratinocytes | 90% of epidermal cells, produce keratin (tough, fibrous protein) |
Melanocytes | 8% of epidermal cells, contain melanin (red-yellow or brown-black pigment) that absorbs damaging UV light |
Langerhans cells | Originate in red marrow, migrate to epidermis, assist in immune response agaisnt microbes that invade skin |
Merkel cells | In deepest layer of epidermis, contact with tactile disc, touch sensations |
Cateogization
Rapid vs. slow adapting
Rapid adapting: quickly sense stimuli, but fall silent if stimuli remains
Slow adapting: will continue to sense as long as stimuli remains
Small vs. large field
Small field: detects stimuli form a smaller surface area, more specific
Large field: detects stimuli from a larger sruface, more general
Sensors
Eccrine Sweat Glands More common Found throughout skin, especially on forehead, palms, and soles Located deep in dermis Sweat cosnsits of water, ions, urea, and ammonia Thermoregualtion
| Appocrine Sweat Glands Found int he skin of armpits, groin, and beard region in men Begint o function at puberty Located in the hypodermis, open into hair follices Sweats contains lipids and proteins Can appearmilky or yellowish NOT involved in thermoregulation
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Hair, or pili, are present on most skin srufaces, except the palms, digits, soles 2 types of hair Temrianl ahir
Vellus hair
Childhood - all vellus except eyebrows, eyelashes, and scalp Puberty- hormones cause vellus hairs in armpits and pubic regions to become terminal ahirs, as well as face, limbs and chests for boys Adulthood- men 95% terminal, 5% vellus, women 35% termianl, 65% vellus
Anatomy of a hair Shaft: superficial protion, projects above the surface o fskin Root: deep to the shaft, penetrates into the dermis, sometimes hypodermis
Both consist of 3 layers Medulla (inner layer) Cortex (middle layer) Cuticle (outemrost layer)
Under normal circumstances: hair emerges at an angle form skin Under physiological/emotional stress (cold/frightened): arrector pili cotnract, pulls hair perpendicular to skin, goosebumps
Hair Growth: Growth stage (2-6 years)
Regression stage (2-3 weeks)
Resting stage (3 months)
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Nails: are tightly packed, hard, dead, epidermal cells Each consists of:
Functions: Protection agaisnt trauma to ends of digits Ability to grasp and manipulate objects Ability to scratch Average fingernail growth = 1 mm/week
Factors taht affect nail growth: |
Glands: epithelial cells that secrete a substance 2 main types of glands
Sebaceous (oil) glands Prevents hair from drying out Keeps skin soft and pliable Prevents water evaporation Inhibits growth of some bacteria
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Sudoriferous (Sweat) Glands: Divided into 2 types: Eccrine sweat glands Apocrine sweat gladns
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Skin Healing: Epidermal Wound Healing Basal cells enlarge and migrate across the wound They continue migrating until they come in contact with another cell, a response called contact inhibition Basal stem cells divide and replace the ones that have moved into the wound
Deep Wound Healing Deep wound: when an injury extends to the dermis and hypodermis, heaking more complex, scar tissue, loss of function
Occrus in 4 stages Inflammatory phase
Blood clot forms, loosely uniting wound edges Vasodilation allows movement of immune cells into tissue
Migratory phase
Proliferation stage
Maturation stage
Scars: 2 types Hypertrophic scar: remains within the boundary of the original wound Keloid scar: extends beyond the boundaries into normal surroiunding tissue
Burns Burns: tissue damage and cell death caused by intense heat, electricity, chemicals, or UV radiaiton (sunburn)
Classified by severity First degree - only epidermis Second degree - epidermis and upper dermis, blisters Third degree - entrie skin, appear blackened, painless (nerves desotryed), regeneration not possible
Skin graft Damaged skin is removed Autograft: tissue from a different part of the patients body is grafted Allograft: tissue froma donor is grafted Can reduce time spent in hospital and improve appearance and function of injured tissues
Two life-threatening problems from burns: Loss of fluids
Risk of infection
Burned skin is sterile for 24 hours Afterwards, pathogens can easily invade the area Infection is the leading cuase of death in critical burn victims
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Reduced blood vessels in dermis Smoothing of dermal papillae
Collagen Decrease in amount Stiffen, break apart, lose shape Results in wrinkles Accelerated by sun exposure
Eslatic fibers
Melanocytes
Sebaceous (oil) glands Decrease in size Dry, broken skin Higher risk of infection
Sudoriferous (sweat) glands
Hair Decrease inf ucntioning of melanocytes through aging Less melanin rpoduced Less melanin deposited in keratinocytes that make up hair Resutls in gray/white hair Eventually hair follicle will stop rpoducign keratinocytes → hair thinning/balding
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Module 6: Nervous System
The nervous system carries out a complex array of tasks
It allows us to sense smells, produce speech, and remember the past, as well as control body movements and regulate internal organs
3 basic functions
Sensory function
Integrative function
Motor function
Central Nervous System (CNS) Brain and spinal cord Integrates (processes) incoming information (inputs) Sources of thoughts, emotions, memories Sends outgoing instructions (outputs)
| Peripheral Nervous System (PNS) All nervous tissue outside CNS Cranial nerves: carry to and away brain Spinal nerves: carry to and away spine Ganglia: relay stations
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Afferent: carry input from sensory to CNS
Efferent: carry output from CNA to effector
Afferent (Sensory) Nervous System Somatic sensory fiber; carry impulses from skin, skeletal muscle, joints Visceral sensory fiber: carry impulses from internal organs
| Efferent (Motor) Nervous System Carry impulses from brain/spinal cord to effector organs, muscles, glands Divided into somatic and autonomic
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Somatic (Voluntary) nervous system | Autonomic (Involuntary) nervous system Automatic, cardiac muscles, smoot muscles, glands, divided into sympathetic and parasympathetic
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Sympathetic | Parasympathetic |
The CNS is protected by several layers: Dura mater (outermost, leathery) Arachnoid mater (middle, web) Pia mater (inner, delicate)
LEAST permeable blood vessels in the body Only water glucose, and essential amino acdis pass through Metabolic wastes, toxins, proteins, and most drugs prevented
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Cerebral hemisphere divided into 4 lobes Frontal lobe Parietal lobe Occipital lobe Temporal lobe
Frontal Lobe Prefrontal cortex: higher intellectual thinking (concentration, planning, decision making, personality)
Parietal Lobe Body areas with more sensory receptors (fingertips, lips) have a larger portion of the soamtic sensory area dedicated Left hemisphere processes input from right side, while right hemisphere processes input from left side
Occipital Lobe
Temporal Lobe Audiotry (hear), olfactory (smell), gustatory (taste) Wernickes area (left hemsiphere only): comprehension of writing/speech Hippocampus: memory and learning Amygdala: emotion and social behavior
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Midbrain: conveys ascending and descending impulses, some reflexes
Pons: control of breathing
Medulla oblongata: controls heart rate, blood pressure, breathing, swallowing, and vomiting
“Cauliflower-like” cerebellum, projects form underneath the occipital lobe
Balance & equilibrium
Body movmeents smooth and corrdianted
Compares brains “intentions” with actual body performance and sends corrective measures when appropriate
The diencephalon (interbrain): sits atop the braisn stem, enclosed by cerebral hemispheres
Thalamus: relay stationf or sensory impulses to somatic sensory area
Hypothalamus: autonomic nervous system (body temperature, metabolism) and primal drives/emotions (thirst/appetite, pain/pleasure)
Epithalamus: forms cerebrospinal fluid
Gray matter: outer, “wrinkled” White matter: inner, squishy Corpus callosum: connects left and right hemispheres and allows them to communciate
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The spinal cord is a continuation of the brain stem that is 14 inches long
Provides a two way conduction pathways to and from brain
Major reflex center
Do not require thinking (no cerebral hemisphere)
React automatically
Evolutionary
The PNS is made up of the nerves and ganglia found outside the CNS
Nerves: bundles of neuron fibers wrapped in connective tissue
Endonerium: delicate connective tissue surrounding individual neuron fiber
Perineurium: courser connective tissue that wraps around groups of fibers to create bundles, called fascicles
Epineurium: tough connective tissue that wraps fascicles together to form nerve
Classification
Sensory (afferent) nerves: form PNS to CNS
Motor (efferent) nerves: from CNS to PNS
Mixed: cotnain boths ensory and motor nerve fibers
Ganglia: structures cotnaining cell bodies of neurons and support celsl that function like relay stations - one nerve enters and another exits
Root ganglia: between nerves of the CNS and PNS (near spine)
Terminal ganglia: between nerves of the PNS and effectors (target cell)
Based on direction of signal…
Preganglionic neuron: neuron before the ganglion
Postganglionic neruon: neuron after the ganglion
Interneuron: neuron beteen two neurons
Neurogila The supporting cells of the nervous system = neuroglia (“nerve glue”) Neurogila function to support, insualte, and protect delicte neurons include
Astrocytes Microglial cells Ependymal cells Oligodendrocytes Schwann cells Satellite cells
Astrocytes Star shaped with numerous projects Accoutnf ro nearly ½ of all nervous tissue Anchor neurons to blood supply Blood brain barrier
Microglial cells CNS only Spider like phagocytes Dipose of debris
Ependymal cells Oligodendrocytes Schwann Cells Satellite cells |
Neurons: Whitish, fatty material, appears waxy Insualts fiber and increases transmission rate of nerve impulse (signal) Wrapped tightly around axon CNS: oligodendrocytes PNS: schwann cells
Most itnerneurons One dendrite, one axon Not myelinated
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Nuerons ahve two amjor properties: Irritability: ability to respond to a stimulus and convert it to a nerve impulse Conductivity: ability to transmit the impulse to other neurons/muscles/glands
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The membrane of a resting neuron is polarized (electrical condition)
Fewer positive ions on the inside than the outside
Major positiv eion inside: potassium (K+)
Major positive ion outside: sodium (Na+)
As long as the inside remains more negative than the outside, the neuronw ill rmeain inactive
A stimulus can cause this to change senasations (light, sound, pressure) to receptor or neurotransmitters from another neuron
Step 1: depolarization Normally, sodium iosn cannot diffuse throught he memrbane, but when the neuron si stimulated, “sodium gates” in membrane opne
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2. Repolarization Potassium rushes out Restores electrical condition to resting state (more positive outside than inside) = repolarization Until repolarization occurs, a neuron CANNOT conduct another a impulse
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Refractory Period
At this point, there is more potassium outside, and more sodium inside To returnt he neuron to its initial ion concentration, a “sodium-potassium pump” is activated
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Resting state
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Action potential (impulse): is an electrical signal, therefore it can be measured in volts
-70 mV = resting state of neuron
-55 mV = threshold needed to be met for action potential to be conducted
+40 mV = voltage of action potential traveling down axon
Saltatory Conduction: faster type of conductiont hat occurs on myelinated axons
Neurons do not touch othe rneurons or effector cells. They communicate across a gap called a synapse
Since the electrical signal of an action potnetial cannot be carried across most synapses, it must be converted to a chemcial signal such as neurotransmitters
Action potential arrives
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Synaptic vesicles
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neurotransmitters
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receptors
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Ion channels
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Neurotransmitter re-uptake
Neurotransmitters are relased from receptors and ion channels close Neurotransmitters can be broken down, or recycle (returned to the presynaptic neurons axon terminal) Process that many drugs manipulate f
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