Human Body: Requirements for Life

• The human body is a organized system of cells, tissues, organs, and organ systems working together to maintain life.

Requirements for Maintenance of Life

• Oxygen is crucial for chemical reactions, allowing cells to break down food and release energy.
• Brain disorders or death happens after five minutes without oxygen.
• Nutrients include water, energy-yielding and body-building nutrients, and micronutrients (vitamins and minerals).
• Water constitutes 60%-80% of body weight and helps to transports nutrients, regulate temperature and lubricates joints.
• Body temperature must maintain range 37°C (98.6°F) with enzymes facilitating chemicals reactions
• Sweating helps cool the body; shivering helps warms it.
• Atmospheric pressure affects breathing, it is the pressure exerted by mixed gases (nitrogen, oxygen) in Earth's atmosphere.
• High altitudes with reduced pressure cause shortness of breath, confusion and nausea.
• Low pressure can cause nitrogen bubbles to block blood vessels.

Homeostasis and Metabolism

• Homeostasis is the ability to maintain a stable internal environment.
• It requires constant communication within the body using the endocrine and nervous systems.
• Metabolism involves catabolism, breaking down complex substances and anabolism, building complex molecules.
• Metabolic actions are regulated by hormones from endocrine glands.

Anatomical Position and Directional Terms

• Anatomical position = body is erect with arms at sides, palms forward.

Directional Terms

• Anterior (or ventral) = front of the body e.g. toes are anterior to the foot.
• Posterior (or dorsal) = back of the body e.g. teeth are posterior to the lips.
• Superior (or cranial) = above e.g. forehead is superior to the nose.
• Inferior (or caudal) = below e.g. navel is inferior to the nose.
• Lateral = side e.g. arms are lateral to the chest.
• Medial = middle e.g. the heart is medial to the lungs.
• Proximal = near point of attachment e.g. the elbow is proximal to the wrist.
• Distal = farther from attachment e.g. the knee is distal to the thigh.
• Superficial = closer to the surface e.g. the skin is superficial to the bones.
• Deep = farther from the surface e.g. the brain is deep in the skull.
• Intermediate = between two structures e.g. the armpit is intermediate the breastbone and shoulder.

Regional Terms and Landmarks

• Used to identify specific body areas:
  • Anterior:
    • Abdominal: anterior body trunk, inferior to the ribs.
    • Acromial: point of shoulder.
    • Antecubital: anterior surface of elbow.
    • Axillary: armpit.
    • Brachial: arm.
    • Buccal: cheek area.
    • Carpal: wrist.
    • Cervical: neck region.
    • Coxal: hip.
    • Crural: leg.
    • Digital: fingers and toes.
    • Femoral: thigh.
    • Fibular: lateral part of leg.
    • Inguinal: area where thigh meets body trunk; groin.
    • Nasal: nose area.
    • Oral: mouth.
    • Orbital: eye area.
    • Patellar: anterior knee.
    • Pelvic: area overlying the pelvis anteriorly.
    • Pubic: genital region.
    • Sternal: breastbone area.
    • Tarsal: ankle region.
    • Thoracic: chest.
    • Umbilical: navel.
  • Posterior:
    • Cephalic: head.
    • Deltoid: curve of shoulder.
    • Gluteal: buttock.
    • Lumbar: area of back between ribs and hips.
    • Occipital: posterior surface of the head.
    • Popliteal: posterior knee area.
    • Sacral: area between hips.
    • Scapular: shoulder blade region.
    • Sural: posterior surface of the lower leg.
    • Vertebral: area of spine.

Body Planes and Sections

• Sagittal section = divides the body into left and right parts.
• Midsagittal/median section = divides body into equal left and right parts.
• Frontal (coronal) section = divides the body into anterior and posterior parts.
• Transverse section = divides the body into superior and inferior parts.

Body Cavities

• The dorsal cavity is divided into the cranial cavity (brain) and spinal cavity (spinal cord).
• The ventral cavity contains the thoracic cavity and abdominopelvic cavity, which includes the abdominal and pelvic cavities.
  • Abdominal cavity contains the stomach, liver and intestines.
  • Pelvic cavity contains reproductive organs, bladder and rectum.

Anatomical Terms for Movement

• Flexion is when the angle between two body parts decreases.
• Extension is when the angle between two body parts increases.
• Abduction is when the movement is away from the midline of the body.
• Adduction is when the movement is towards the midline of the body.
• Elevation is movement in the superior direction e.g. shrugging shoulders.
• Depression is movement in the inferior direction e.g. lowering shoulder after shrugging.
• Pronation = palm facing down.
• Supination = palm facing up.
• Dorsiflexion = foot points superiorly.
• Plantar flexion = foot points inferiorly.
• Palmar flexion refers to the hand.
• Medial rotation is rotational movement towards the midline (internal rotation).
• Lateral rotation is rotating movement away from the midline.
• Inversion = sole of the foot moves towards the median plane.
• Eversion = sole of the foot moves away from the median plane.
• Opposition = thumb touches a finger.
• Reposition = thumb and little finger move away from each other.
• Circumduction = conical movement of a limb from the joint.
• Protraction = anterolateral movement of the scapula.
• Retraction = posteromedial movement of the scapula
• Excursion = side-to-side movement of the mandible.
  • Lateral excursion moves the mandible away from the midline.
  • Medial excursion returns the mandible to its resting position.

Levels of Organization

• Chemical level (atoms) to molecules, macromolecules, organelles, cells, tissues, organs, organ systems, organism.

Elements and Compounds

• The body consists of oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, iron, sulfur, potassium, etc.
• Inorganic compounds (H2O, salts, acids, bases, CO2) do not contain both carbon & hydrogen.
• Organic compounds (glucose) contain both carbon & hydrogen.
• Adenosine Triphosphate (ATP) is the body's fundamental molecule of energy transfer.

Cell Organelles

• Nucleus consists of the cell's DNA and surrounded by nuclear envelope with nuclear pores
• Nucleolus produces ribosomes.
• Ribosomes are made of RNA and protein, for protein synthesis.
• Mitochondria generates chemical energy and chemical energy produced by mitochondria is stored in ATP.
• Endoplasmic reticulum (ER) synthesizes, folds, and modifies protein molecules.
  • Rough ER contains attached ribosomes.
  • Smooth ER is for carb & lipid synthesis, detoxifies compounds and assists in muscle contraction.
• Golgi apparatus processes and packages protein/lipid molecules.
• Lysosomes break down excess/worn-out cell parts or destroy invaders.
• Peroxisomes contains enzymes for reactions and break down substrates.
• Cytoskeleton helps maintain cell shape, elasticity and stability.
• Vacuole stores substances depending on cell type.
• Centrosome organizes microtubules and pulls chromatids apart during cell division.
• Cytoplasm is the semi-fluid material where organelles are embedded.
• Cell membrane surrounds organelle.
• STEM cells are unspecialized and can develop into specialized cells.

Specialized Cells

• Bone cells composes major part of skeletal system for: support, protection and movement.
• Blood cells functions from transporting of oxygen and fights infection
• Muscle cells are tissues enables all bodily movement for skeletal, cardiac, and smooth muscle.
• Fat cells is component of adipose tissue & contains stored fat.
• Skin has layer of epithelial tissue to supports connective tissue that protects internal structures.
• Nerve cells sends signals from the brain & spinal cord via nerve impulses.
• Endothelial cells form the inner lining of the cardiovascular/lymphatic systems.
• Sex cells is reproductive cells that create new life.
• Pancreas functions as exocrine and endocrine organ that regulate blood glucose and digests food.
• Cancer cells development of abnormal cell that divide uncontrollably.

Histology and Tissue Types

• Histology is the study of tissues.
  • Epithelial tissue covers body surfaces and cavities.
  • Connective tissue binds cells and organs.
  • Muscle tissue helps movement.
  • Nervous tissue sends electrochemical signals

Epithelial Tissue

• Epithelial tissue characteristics inclue closely fit cells, has a apical surface, rests on a basement membrane, no blood supply and regenerates easily.
• Can have Squamous (thin), Cuboidal (boxy) and Columnar (rectangular).
• Classified as = simple (one layer), stratified (multiple layers) or pseudostratified (single layer but looks like multiple).
• Simple epithelium = absorption, secretion and filtration:
• Simple squamous epithelium = single layer/thin fit, forms membranes in lung/capillaries which used for filtration.
• Simple cuboidal epithelium = glands and ducts.
• Simple columnar epithelium = single layer tall cells, lines from stomach to the anus.
• Pseudostratified columnar epithelium = absorption and secretion, lines respiratory tract.
• Stratified epithelium
  • Stratified squamous epithelium – multiple layers, found in the friction areas.
  • Stratified cuboidal epithelium – one or two layers, selective absorption, specializes in glands into the blood/lymph.
  • Stratified columnar epithelium – columnar cells, found in large organs.
  • Trasitional Epithelium – multiple layers, urinary bladder/uters/urethra, for stretching.

Glandular Epithelium

• Gland = secretes water and protein molecules.
• Exocrine glands secrete sweat and oil through ducts.
• Endocrine glands secrete hormones directly into blood.

Connective Tissue

• Connective tissue connects body parts.
• Features = most tissues have blood supply except tendons, ligaments and cartilage.
• Matrix contains: ground substance (H2O), collagen, water
• Types = bone, cartilage, connective, loose, blood
  • Bone
    • Hard, from Ca^2+
    • Supports and protects body
    • Has bone cells sitting in lacunae
  • Cartilage = Flexibility Most widespread is -Hyaline
    • Rubber/glass apperence, blue/white
    • Hyaline cartilage lines the larynx, attaches the ribs where joints form and skeleton fetus. -Firbrocartilage
    • Forms disk in the vertebral column
    • Elastic
      • Supports external ear
  • Dense Connective Tissue
    • The maxtrix element is the packed collagen, with rows of fibroblasts
  • Loose Connective Tissue
    • Soft/more fibres
    • Areolar is cobweb, cushions and protects the body, fluid matrix contains fiber (forming loose network)
    • Adipose is body fat protects organs/insulates.
  • Reticular
    • Interwoven of reticular fiber, resemble fibrolast
  • Blood
    • Vascular tissue, consisting of blood cells, surrounded by fluids

Muscle Tissue

• Muscle tissue has contractions that provides movement
  • Skeletal
    • Attached to the skeleton
    • The cells of muscles are cylindrical, multinucleate with visible striations.
  • Cardiac
    • Only in the heart
    • Striations, cell is uninucleate, branching cells contain gap injections/ interraclated disks.
  • Smooth
    • Spindle and shaped, singe nucleus
  • Elasticity returns its origin, Extensibility stretches and contracts

Nervous Tissue and Membranes

• Nervous tissue consists of neurons, receives and helps the body conduct to electrochemical impulse. -Tissue membrane that covers inside/outside
• Connective tissue membrane has connective tissue and membrane -Lines the movable joint, reduces the joint friction -Made of connective tissues (around kidney,)
• Epithelial tissues attached the connective tissue

1. Mucous membrane (mucosa)
   • Lines body and the digestive track
2. Serous Membrane
   • Does not open to external environment and supports the lubricating membrane reducing friction

• Cutaneous Membrane
  • Multiple/ Connectives tissues and epiltheal - The skin

Organ Systems

• Organ system group that work together to do specific functions in the organism
• Made of 11 integrated organ system,

1. Endocrine
   • Hormone/regulation -Reporductive
     • Makes reproductive calls to generate offsping/produces 2)Intregumentary
   • protect external envrioments and regulates temperatures 3)Muscular
   • voluntary/involuntary movements - Skeletal Supports for internal organs
2. Urinary system
   • Filters blood of waste for excretion
3. Lymphatic -
   • Regulates lymph, maintains the blood
     • Cardivascular System
     • Regulates blood, controls hormone output. -Nervous System
       • Process center of sensory by responses

Body Support and Movements

• Human body has 620 muscle, 206 bones where skeletal/muscle are at work
• System provides system for digestive/vision and regulate tempreatures and protection
• Skeletal system Supports body/protect organs/produces blood & store minerals and fats

Bones Parts

• Fibrous - the skeleton of the fetus; some parts of the skeleton ossify.
  • Endochondral- the ossification of hyaline of cartilage
    • Osteogesnesis -The process of bone formation 1) intramembranous Ossification - The membranes are formed A) messenchymal Stem cells * - Can differ in many ways: osteoblasts bone/ Chondoryce - Cartilage / Myocytes (muscle/
  • Trabucule - Has compact cells and trabecule A) Osteocyte Bone cell trapped inner.The bone matrix B) trabecule - thin plates C) osteoid –un mineralized tissue . -D) large cell resposibale for synethis of minerals

3. osteoclas - breaks tissue down critical with acid
4. chodryocytes –Cartilage.
5. vascular 6) early humna - Resorption beings

Bones Structure and Anatomy

• Has three types: Long: cylinder The shaft with bone Medullary cavity Bones ends are wiider called Short bones cube shaped - ankles and joints - supply’s stability
  • flat - Thin and used for sketal muscles and points of attachment protect organs.
  • Irregular- Complex shape- vertebrae cord protects from compression. Sesmoid that reduce help from pressuring joints
  • Cartrilage covers surface that joints with other ligaments

Joints and Connections Classification

• Where there bones connected with structures where
• Connect Tissue - Cartiligous joints - hylaine and carlidge - Synovial bone is directly contact

Structure

• Amount determined adjacently.
• Cartulage

Energy

Skeletal is for body movements Actin -

• Myasin filaments contraction Epimysium

• Allows for muscle maintainance

• Fiascle- Tissue to allow muscle independent movements cells has endimycisuim

• Has nutrients help supply muscle fibres

• Has sarconomere that connect s

• Fibres bundle for cell. Contracrions - Sacromeme of fibers SacroPlasm

• Storages/ releases Connect with actins - to perform movement when signiled

• Required Trphospphate ATP to remove ATP to contract ,

  • Muscles store high amounts of ATP required to remove ATP to constract

• elasticity

• returns to original length ATP

• ATP supples energy for the contraction Creating phosphate

• Glycolsys*

  • Anaerobic, breaks for high glucose

• Aerobiuc restpitation*

  • Rest with the presence of gluclose ciruling in bloodstream
    • Muslces stored oxyegn.

• Moblion allows cient contraction

• Areobbic system increases to to suppplty O2 to help for long muslces