MEDS1002 Study Plan PDF

MEDS1002 STUDY PLAN Skin Lecture ASSOCIATED STRUCTURES - Hair and hair follicles - Sebaceous glands (secrete sebum into hair follicles) - Sweat glands (temperature regulation and toxins) - Nails (plates of keratinised cells) Layers -...

MEDS1002 STUDY PLAN Skin Lecture ASSOCIATED STRUCTURES - Hair and hair follicles - Sebaceous glands (secrete sebum into hair follicles) - Sweat glands (temperature regulation and toxins) - Nails (plates of keratinised cells) Layers - Epidermis o Keratinocytes ~ 85% o Varied THICKNESS dependent on function o Soles and palms = thicker = without hair follicles o Cells differentiate as they move up layers, exfoliated from surface - Dermis o Tensile strength and stretch o Contains collagen and elastin fibres o Responsible for finger print (between epidermis and dermis) - Hypodermis o Consists of adipose tissue, loose connective tissue, subcutaneous fat, superficial fascia o Anchors to underlying structures o ENERGY STORAGE o INSULATION o Varied THICKNESS CASE STUDY: ACNE CASE STUDY: SUNBURN Results from: Protection: Melanin - Accumulation of dead skin cells and - Pigment which absorbs / scatters UV and keratin vis-light - Excess sebum production - Bacterial proliferation / inflammation Consequences - Inflammation - Scarring Solutions - Accutane o Vit A o Reduces sebum production o Anti-inflammatory o Reduced bacterial growth o Shrinks sebaceous glands CASE STUDY: BOTOX Blocks nerve cells causing muscle contraction and sweat gland activation Fascia lecture Glossary Fascia: Layer of strong, flexible connective tissue covering/separating/holds together various organs/muscles/vessels/nerves Sheath: covering of connective tissue Viscera: internal organs Connective tissue: main tissue type consisting of fibroblast cells and collagen fibres Tendon and aponeuroses: attach muscle to bone Parietal: wall of body cavities Ligaments: attach bone to bone Fascia is… → Mostly DENSE REGULAR (or IRREGULAR) connective tissue → Collagen = arranged in bundles, running parallel to each other Superficial ROLE Loose connective tissue + adipose - Protection and cushioning from impact Contains sweat glands/vessels/cutaneous - Fat storage nerves - Anchors skin - Facilitates movement/flexibility - Pathway for nerves and vessels - Contains immune cells Deep ROLE Surrounds/separates BONES, MUCLES, - Support and structure of muscles NERVES, and VESSELS - Muscular force via tendons, ligaments and Dense REGULAR/IRRECULAR connective aponeuroses tissue - Compartmentalisation 3 layers… - Prevent infection/inflammation Proverbial Covers cervical vertebra and - Reduces friction sheath associated muscles - Support vessels and nerves Pre- Supportive framework for - Detects changes in tension/pressure and tracheal anterior neck structures, pain sheath facilitates movement during Classifications… swallowing/speaking Epimysia Surrounds muscles Carotid Protects carotid arteries, jugular Intermuscular Compartmentalisation sheath vein, and vagus nerve septa Aponeuroses Wide attachment area Retinacula Surrounds joints Investing Surrounding neurovascular bundles  APONEUROSES - Sheet of pearly white connective tissue - Attaches muscles (requiring qide attachment areas) - EG palms and soles - 2 Serosal layers associated with fascia… Visceral Parietal Surrounds organs of thoracic, Lines walls of abdominal, and pelvic cavities body cavities (organs that move or move next to each other) ROLE - Facilitates organ movement against each other - Facilitated by fluid in interstitial space NOTE: a “real space” is made between visceral and parietal layers → epithelial cells secrete fluid to reduce friction of organ movement Injuries to SCALPS bleed profusely… why?? S → skin Move as a unit, tightly connected, arteries C → connective tissue (superficial) unable to retract (help open by fascia) A → aponeuroses L → loose connective tissue P → periosteum CASE STUDY: issues 1. Overuse / repetitive stress of muscles 2. Trauma – sprain, strain, tear 3. Infection 4. Autoimmune disorders (arthritis) 5. Biomechanics (abnormal gait, poor posture) 6. Natural aging 7. surgery Muscles lecture Skeletal muscle attachments: - contractile component of the muscle (red) = the belly (can be split into two or more heads) - must be attached to two points (tendons = way muscle attaches) - upon contraction the two points move closer together - attach to bone via TENDONS - attach to bone via APONEUROSES TENDON LIGAMENT → Dense fibrous connective tissue (organised → Similar materials collagen bundles) – don’t contract → deep in the body → attach muscles to BONE → attach BONE to BONE → rounded/strap-like cords → surrounds bone joints TYPES OF MUSCLES INTRINSIC EXTRINSIC Both attachment points within one area of the One has one attachment within one body body structure, one beyond it MUSCLE SHAPE: MUSCLE SHAPE: pennate Flat - feather-like - parallel - unipennate (muscle fibres insert fibres at angle to one side of tendon) - may be wide - bipennate (muscle fibres insert - may have at angle to both sides of tendon) aponeurosis - multipennate (collection of - may be thin bipennates) Can be longer - can contract more MUSCLE SHAPE: Fusiform - spindle shaped Can pack many (most) short angled fibres into a smaller region → pennation = less contraction, but more fibres contracting simultaneously = stronger MUSCLE SHAPE: MUSCLE SHAPE: Circular Convergent - Form a sphincter - possess broad and narrow attachment at either end MUSCLE SHAPE: MUSCLE SHAPE: multiheaded / quadrate multibellied - 4 equal sides - More than one attachment at one end - TENDONS AND LIGAMENTS = attach to bones via Sharpey’s fibres (perforating fibres) = parallel collagen fibres extend into the periosteum and embed into the bone matrix = periosteum is the dense connective tissue layer immediately surrounding bone JOINTS… caused by skeletal muscle Mechanical advantages: 1. Effectiveness of muscle effect on joint varies 2. Length of tendons effects 3. Joint positioning can maximise muscle fibre contractions EXAMPLES OF MUSCLE ACTIONS ON JOINTS FLEXION EXTENSION Bending (decrease angle at joint) Straitening (increase angle at joint) ABDUCTION ADDUCTION Moving away from the midline of the body Moving towards the midline of the body (coronal (coronal plane) plane) EG spreading fingers EG bringing fingers back together  Nerves activate muscle Motor unit= motor neuron (nerve cell) and the muscle fibres it controls Nerves typically activate the muscles they pass through (usually from the deeper side) Wide muscles → nerves stimulate parts individually to alter muscle action TYPES OF CONTRACTION ISOTONIC ISOMETRIC ▪ Muscle changes ▪ Muscle length length unchanged ▪ Movement produced ▪ No movement ▪ Resists gravity and force CONCENTRIC ECCENTRIC ▪ Muscle shortens ▪ Muscle contracting ▪ Movement produced but lengthening ▪ Controlled movement MUSCLE TONE NOTE: muscles are almost always slightly contracted, even when relaxed ▪ Contraction = no movement ▪ Muscles slightly stiff ▪ Maintains posture/stability MUSCLE FUNCTIONS FIXATOR SYNERGIST/S ▪ Steadies’ proximal limb segments ▪ Helps the prime mover ▪ Isometric contraction ▪ Does similar action / steadies joint PRIME MOVER ANTAGONIST ▪ Produces a specific movement ▪ Opposes action of prime mover ▪ Concentric contraction ▪ Eccentric contraction HOW ARE MUSCLES FED FIXATOR SYNERGIST/S Supplied by arteries bringing blood Multiple arteries contracting within muscles PRIME MOVER ANTAGONIST Tendons supplied by blood from muscle bellies ▪ Endurance (isotonic movement) increases and from the bone they are attached to number of blood vessels ▪ Strength training (isometric movement) increases mass of muscle fibres Nerves and Vessels Lectures MUSCLE FUNCTIONS ARTERIES VEINS ▪ Carries oxygenated blood ▪ Carries deoxygenated blood ▪ Blood flow: heart → body ▪ Blood flow: body → heart ▪ Thick elastic walls ▪ Less thick and elastic walls ▪ High pressure ▪ Low pressure ▪ No valves ▪ Valves ▪ Branching LYMPH VESSELS NERVES ▪ Carries excess fluid/plasma proteins/cell ▪ Superficial nerves form networks with debris: interstitial space → venous system vessels (drains from spaces between cells ▪ Deep nerves collect with vessels in ▪ Fluid flow: tissues → heart bundles under deep fascia ▪ Fine, thin walled ▪ Large nerves/vessels may be enclosed in ▪ Needs pressure from vessels and muscles fascial sheaths to pump ▪ Abundance: where body contracts exterior skin/mucosa/submucosa of respiratory/GI systems/membranes ▪ Limited: muscles/bone/fascia ▪ Absent: CNS ▪ Drainage: Drain into lymphatic ducts (lymph vessels that merge together): lymph → blood TYPES OF CIRCULATION PULMONARY SYSTEMIC Heart → lung, heart → lung Blood begins deoxygenated → supplied to heart Blood begins deoxygenated (from body) → → lungs → oxygenated reoxygenated when pumped to lungs Blood begins oxygenated → supplied to body → deoxygenated General order: artery → arteriole → capillary → venule → vein JOURNEY OF BLOOD FROM DEOXYGENATION TO OXYGENATION ^^ general systematic circulation ^^  RIGHT VENTRICLE→ PULONARY ARTERIES → CAPILLARY BEDS (IN LUNGS) → GAS EXCHANGE → OXYGENATED BLOOD (FROM VENULES) → LEFT VENTRICLE (VIA VEIN) THE HEART MECHANISMS = 2 sided = 2 pumps = 4 chambers = 2 atria receive blood from veins = 2 ventricles pump blood to arteries RIGHT SIDE receives deoxygenated blood (loss pressure pump = thinner walls) LEFT SIDE receives oxygenated blood (higher pressure pump = thicker walls) Venous plexuses = intercommunicating networks of veins - Cushioning effect around nervous tissue (spinal cord) - Wick heat off hot blooded artery (spermatic cord Venous plexuses = intercommunicating networks of veins - Cushioning effect around nervous tissue (spinal cord) - Wick heat off hot blooded artery (spermatic cord Venous sinuses = endothelial-lined spaces with cranial cavity (drainage) LYMPHATIC SYSTEM ROLE: drains excess tissue fluid, cleans up debris → lymph: when fluid enters a lymphatic vessel → lymph is typically clear/colourless → GI lymph’s carry lipids = can have milky appearance  FACTORS AFFECTING LYMPH FLOW → Filtration pressure in tissue space → Vessel compression → Gravity and pressure → valves create unidirectional flow → No pump Lymphatic organs… ◼ produce lymphocytes (type of white blood cells) → consists of thymus gland, bone marrow ◼ initiate immune response against antigens  NERVOUS SYSTEM CNS ROLE Make sense of stimulation (sensory input) Initiates responses (motor output) Facilitates response to internal and external environments PNS ROLE Collects and transports sensory input External → internal environments (CNS) Collects and transports motor output Internal (CNS) → external environments Nerves in the head = optic = trigeminal Spinal nerve = intercostal nerve = vagus = phenic = sympathetic trunk PNS = radial = ulnar Bone Lectures BONE FUNCTION ◼ enables movement  ◼ provides support ◼ protects organs ◼ store/release minerals ◼ production of red blood cells Cells involved in remodelling Remodelling consequential of altered muscle use Osteoclasts (cells removing bone) Osteoblasts (cells adding bone) TYPES OF BONE CANCELLOUS CORTICAL - porous - outside - spongy - dense/heavy - light - outside of bone - inner bone and at the ends of long bone - less porous MADE OF… HYDROXYAPATITE: mineral component mainly Ca and P → provides strength and rigidity COLLAGEN: provides elasticity/flexibility (organic) Periosteum definition: fibrous sheath covering bone, containing blood vessels and nerves, providing nourishment and sensation VASCULAR SUPPLY → blood supply to and from bone Principal arterial sources (central arteries): 1. Periosteal 2. Nutrient Both contribute to CENTRAL ARTERIES Venous drainage occurs through corresponding veins 1. Periosteal 2. Venous 3. Central BONE DEVELOPMENT  BONE CLASSIFICATION LONG – TUBULAR SHORT – CUBOIDAL FLAT = USUALLY PROTECTIVE IRREGULAR SESEAMOID – FORMS WITHIN A TENDON, GIVES MUSCLE GREATER FORCE FOR FUNCTION (INCREASED DISTANCE TO EXTEND OVER = GREATER POWER)  MARKINGS AND FEATURES ON BONE CREST (ridge) FORAMEN (opening/hole) – NUTRIENT FORAMEN (takes artery into bone) FOSSA (depression/hollow) TUBEROSITY (roughened prominence for attachment) Forensic lecture Forensic workers - Coroners - Pathologists - Dentists - Anthropologists - mortuary technicians - radiographers - social workers - molecular biologists BIOLOGICAL PROFILING ANCESTRY/RACE SEX → bone structure (bone prominence, face → almost impossible in children projection, nose, mandible) (underdeveloped sex characteristics) → DNA (groups of people sharing same series of → adults – pelvis development and muscle mutations on mitochondrial genome) attachments (overlapping with long bones) → Phenotyping (appearance): issues = hair/eye colour change, skin colour change AGE STATURE/HEIGHT → Children = dental eruption  → Adolescence = dental and bone fusion → Adults (difficult post-40) = growth stopped, degree of osteoarthritis TYPES OF TRAUMA 1. blunt Antemortem trauma: Perimortem trauma: Postmortem trauma: 2. sharp force injury occurring before injury occurring around injury occurring after 3. ballistic/projectil death time of death death e - useful in child - fresh bone = Causes: abuse significant → dogs cases/identificatio collagen → rodents n - fractures are → shape/jagged weathering/erosion - bone bending → plants → burning Estimating postmortem interval IMPORTANCE identify the person, witnesses and suspects PROBLEMS weathering of bone dependent on environment (temperature, humidity, pH, exposure, soil type) which vary enormously METHODS - Cultural associations - Taphonomic factors - Radioactive decay methods Cultural associations in estimating postmortem intervals ABORIGINALS EUROPEAN POSITIONING Exhibit severe tooth wear Restorations/fillings, Prehistoric: flexed/foetal without decay (no sugar, tough crowns/root canal treatment, position diet) implants, orthodontics, veneers Forensic: shallow burial, odd positioning Historic: extended on back RADIOACTIVE DECAY METHODS RADIOCARBON DATING BOMB PULSE C14 DATING  - Uses C-13/14 Testing nuclear weapons of WW2 = significant - Useful from 300-60,000 years atmospheric C-14 concentrations Suitable post 1950s Not useful as time progresses (levels stabilising) Joints Lecture “anthrology” = study of joints “anthroscopy” = scoping of a joint “anthroplasty” = joint replacement “arthritis” = inflammation of joint “articulation” = two bones meeting (eg articulation between the two bones in the forearm) Joint definition: known as an articulation – the site where 2+ bones meet to facilitate movement/support FIBROUS CARTILAGINOUS SYNOVIAL - Bones joined by fibrous Bones joined by: Features: connective tissue a) cartilage - joint capsule - Little to no movement b) cartilage and fibrous tissue - ligaments i) cartilage type = hyaline - synovial membrane and fluid ii) some joins may have pad of - articular cartilage fibrocartilage - sometimes: fat pad, articular iii) slight → no movement discs - freely movable OSTEOARTHRITUS WHAT IS IT? FACTORS AFFECTING Bone-joint inflammation, occurring due to - Mechanical imbalanced joint tissue - Inflammatory repair/destruction/remodelling - Metabolic Comparative Anatomy Lecture LEARNING OUTCOME: identify bones, bony features, and tooth types of the human skull Human teeth = unspecialised Bony pelvis = hip bones and sacrum  COMPARING HUMAN LIMBS LOWER LIMB - Similarities across species = usually used for locomotion - In quadrupedal mammals weight bearing on lower limbs ANIMALS BASIC VERTEBRATE LOWER LIMB - For animals dependent on running PLAN → increasing length of distal limb segments increases the distance covered with stride → longer distal segments cover more ground for same energy expended → reduced animal digits and slender bones reduces energy required to swing limb → more digits increase manoeuvrability for short energetic bursts → long distance = less toes → JUMPING ANIMALS: lower limbs highly flexed – muscle levelrage, large feet increase locomotion → SWIMMING AND FLYING ANIMALS: lower limbs = flippers, not weight bearing Histology lecture HISTOLOGY VS PATHOLOGY HISTOLOGY PATHOLOGY study of body’s cells and tissues / how tissues are study of abnormal / diseased tissue organised into organs STEPS INVOLVED IN TISSUE PROCESSING 1. SPECIMEN ACQUISITION 2. FIXATION to preserve structure 3. DEHYDRATION to remove water 4. EMBEDDING stiffen to cut 5. SECTION improves resolution 6. STAIN produces contrast, specific identification of structures STEPS INVOLVED IN TISSUE PROCESSING 1. SPECIMEN ACQUISITION fresh tissue 2. FIXATION to preserve structure 3. DEHYDRATION to remove water 4. EMBEDDING stiffen to cut 5. SECTION improves resolution 6. STAIN produces contrast, specific identification of structures Magnification: enlarging the size of an object through optimal instrument Resolution: ability to distinguish between two closely spaced objects / images → Low resolution = blurry / less distinct Viscera Lecture Viscera means ‘internal organ’ → typically protected by superficial bone, muscles, or fat  BODY SYSTEMS SYSTEMIC ANATOMY REGIONAL ANATOMY → structures that work together → structures located together → various locations → PRO: focus on one ‘body area’ at a time → PRO: focus on one body function at a time → CON: sometimes unrelated functions → CON: hard to draw correlations with other systems  VISCERA OF CRANIAL CAVITY (+ VERTEBRAL) - Brain – cerebral hemisphere - Brain – cerebellum - Brain stem - Spinal cord VISCERA OF THORACIC CAVITY VISCERA OF ABDOMINAL CAVITY VISCERA OF PELVIC CAVITY Viscera 2 lecture Viscera of the cranial cavity and their relationships Cerebral hemisphere: controls voluntary motor actions, sensory processing, emotional control, higher thought processes Cerebellum: controls physical movements, regulates balance learned movements, controls motor coordination - VOLUNTARY Brain stem: connects brain and spinal cord, controls INVOLUNTARY Spinal cord: communicates sensory, motor and autonomic messages between brain and body (interacts with external environment, controlling internal environment) Viscera of the thoracic cavity Right lung Lateral to heart, great vessels, trachea, bronchi, and oesophagus Heart and great vessels Medial to lungs, anterior to trachea and oesophagus Left lung Lateral to heart, great vessels, trachea, bronchi, and oesophagus Trachea and bronchi Posterior to heart, anterior (passage for air in and out of to oesophagus, medial to lungs) lungs Oesophagus (passage for Posterior to heart, trachea food and drink into stomach) and bronchi, medial to lungs Thyroid gland (makes Superior to heart and lungs, thyroid hormone – gets oxygen anterior to trachea and into cells from metabolism) oesophagus Viscera of the abdominal cavity Liver (makes bile, processes blood to removes Small intestine (absorption of nutrients) waste, breakdowns harmful GI substances) Stomach Spleen (filters/stores blood, produces white blood cells/antibodies, destroys old red blood cells) Gall bladder (stores bile) Right kidney (filters blood, eliminating excess fluids and salts, removes wastes) Large intestine (removes water from digested Left kidney food) Duodenum (chemical digestion of partially digested food, site for bile and pancreatic enzyme, absorbs water, electrolytes, and nutrients) Pancreas (makes enzymes to digest protein, fat, sugar, controls BGL, makes endocrine hormones (insulin/glucagon)) Viscera of the pelvic cavity Urinary Stores urine made by kidneys bladder Ureter Passage for urine from kidney → bladder Ovary Produces female gametes, secretes hormones Uterus Space for protection, supply of oxygen/nutrition, removal of metabolic waste for offspring Vagina Passage in/out of uterus for sperm Prostate Secretes fluid to protect/nourish male gametes, allows ejaculation gland of semen/secretes hormones Urethra Passage for urine from bladder to outside body, for males passage of sperm outside body Large Removes water from faeces intestine Rectum Stores faeces from colon Fertilisation to Neurulation Cellular processes during embryonic development PROLIFERATION DIFFERENTIATION INTERACTION MOVEMENT Rapid divisions of cells One cell turns into Cell communication diving to form different another cell type (many interactions and structures movement) CELL IDENTITY GUIDE CELLS TO DEVELOPMENT TYPES OF CELL SIGNALS a) Gene expression AUTOCRINE SIGNALLING: one cell secretes, acts on b) Protein expression itself c) MicroRNA PARACRINE SIGNALLING: signal released by one d) Epigenetics cell, affecting surrounding cells MORPHOGEN / MORPHOGEN GRADIENTS Crucial for inductive signals Morphogen: instructing molecule for development (come in the embryo) important in establishing signals and gradients Organising organ: structure signalling and affecting surrounding cells (secretes signal) that move across embryo with concentration gradient (high conc. to low conc.) Organising structures resulting in gradient across tube = green and purple (roof plate) = patterning of spinal cord  EMBRYONIC DEVELOPMENT ▪ Female gamete = oocyte (released and travels down fallopian tube) ▪ Haploid cell (23 chromosomes) forms in ovaries ▪ Fertilisation (embryo implantation) occurs in uterus ▪ Hormones prep uterine lining for embryo implant = oestrogen, progesterone ▪ Hormones prep oocyte for ovulation = luteinizing hormone (LH) and follicle stimulating hormone (FSH) ▪ DAY 14 = ovulation ▪ 7 DAYS LATER = embryo formation, uterus ready to receive embryo for implantation ▪ Zygote (single cell pronuclei, diploid 46 chromosomes) formation post-fertilisation THE ZYGOTE Zygote: → single cell pronuclei (2 – 1 from oocyte, one from sperm) → surrounded by zona pellucida (protection and maintains development) → outside = polar bodies (excess) EARLY STAGES OF DEVELOPMENT  SERIES OF MITOTIC DIVISIONS AS IT TRAVELS DOWN THE FALLOPIAN TUBE STAGE 1: Zygote Cleavage = single cell splits STAGE 2: Series of cleavages (cell division) STAGE 3: Cells get smaller with each division STAGE 4: Day 5 Morula formation, compacts and cavitates (cells compacting 16-32 cells) - Cell polarity established: different inside/outside environments (receive different signals) - Cavity formation: cavity forms as fluids rush into embryo - Differentiation: cells evolve to more developed cells (totipotent) → can turn into any embryonic cell → excess cells produce embryonic tissue (yolk or amniotic sac) STAGE 5: Blastocyst formation… main cell populations - Inner cell mass: contain cells that turn into embryo, making nerve/heart cells, supportive tissues (yolk sac) (pluripotency – multiple cell types) - Trophectoderm: outer population of cells (differentiate into the placenta) STAGE 6: DAY 6/7 Blastocyst hatches from zona pellucida - Inner cell mass segregates into two populations of cells - Primitive endoderm (Hypoblast) differentiates into extra embryonic tissue - Primitive ectoderm (Epiblast) forms embryo/foetus STAGE 7: Blastocyst must escape protective structure to penetrate/attach to the endometrium STAGE 8: 8/9 days embryo implants into uterine wall STAGE 9: proliferation of uterus, embryo adheres, attaches, and invades to uterine wall (endometrium) - Invasion of endometrium using trophoblast cells (eventually form placenta) - Epiblast and hypoblast from bilaminar disc - Amniotic cavity formation PREGNANCY TEST OPERATION = trophoblast cells secrete human chorionic gonadotpin (Hcg) hormone Detection ~ 2 weeks post-implantation Tests must be sensitive and specific via urine samples Present hCG binds to antibodies Bilaminar disc formation Epiblast = pluripotent Hypoblast becomes multipotent → differentiates into different cell population Visceral endoderm → forms yolk sac Hypoblast cells migrate and form a cavity (yolk sac)  GASTRULATION BEGINS WITH THE FORMATION OF THE PRIMITIVE STREAK AT THE CAUDAL END OF THE PRIMITIVE ECTODERM Epiblast → primitive ectoderm → germ layer formation Beneath yolk sac supplies nutrients to embryo Primitive streak: site of gastrulation Initial: primitive ectoderm proliferation (cell division) 3 germ layers: 1. Ectoderm: nervous system, skin, hair, nails 2. Mesoderm: forms bone, blood vessels/blood, heart, muscles 3. Endoderm: form epithelial lining of glands/respiratory/GI tracts During development: embryo will turn and fold where endoderm will form inside structures Cells of the node establish embryonic left-right axis ➔ Primitive node/pit: consists of cells (made of cilia) – motile cell specialisation, embryo rotates clockwise distributing signals forming left-right axis ➔ Signal movement in specific direction = structures are unilateral  NEURULATION (DAY 20) Neural plate undergoes neurulation Neural tube formation ◼ Neural plate folding forms neural tube ◼ Primitive ectoderm thickens, elevates, folds ◼ Neural folds converge at the mid line ◼ Neural tube closes ◼ Patterning (different neurons – motor/sensory – at different regions) ◼ Upon neural tube closing: → notochord: organiser, instructs bottom half of neural tube → anterior/dorsal components: different, specific neuron types ◼ Upon closure = two sides = caudal and cranial neuropore Neural tube function o Cells of CNS Neural crest cells o Forms PNS o Melanocytes (skin pigmentation) BODY PLAN FOR ORGANOGENESIS  During embryonic development, primary BRAIN vesicles formed → differentiate to produce secondary brain vesicles ^^ Neural tube patterning ^^ BASIC STAGES OF DEVELOPMENT 1. PREIMPLANTATION 2. GASTRULATION / EARLY ORGANOGENESIS 3. ORGANOGENESIS 4. FOETAL GROWTH AND DEVELOPMENT DEFINITIONS Somatic cells: highly specialised body cells Differentiation: is the process of turning into Progenitor cells: less mature cells: another cell differentiate/replicate Potency: ability to differentiate Stem cells: undifferentiated (cannot turn into Terminally differentiated: cannot differentiate another cell type) = unspecialised  TYPES OF STEM CELLS EMBRYONIC ADULT INDUCED PLURIPOTENT → derived from inner cell mass of → derived from developed → somatic body cells ‘reverted’ the blastocyst organs backwards to pluripotent → pluripotent – differentiate into → multipotent – lineage embryonic stem cell-like cells ~200 body cells restricted (genetic reprogramming) EG BLOOD STEM CELLS - Cells turn into multipotent cell types - Form various blood components o RBC o WBC o Platelets - Highly differentiable - Highly specialised - Aids understanding blood development / factors affecting USES OF STEM CELLS  MOLECULAR REGULATION OF CELL IDENTITY Growth factor: differentiation and proliferation stimulating molecule - Useful for studying cell behaviour - Changes molecular identity of cell - Various growth factors alter concentrations/timings/gradients/affects IDENTIFYING IF YOU HAVE THE RIGHT CELL TYPE PHENOTYPE MOLECULAR MARKERS Not the optimal way (stomach/liver cells look the Proteins and genes same) Cells have molecular identity Example in development: How does the neural plate form the neural tube? Cannot access neural tube in the embryo: invasive/dynamic Use stem cells to help isolate particular events during embryogenesis -> proliferation, differentiation, interaction and movement. Take stem cells -> add growth factors to turn them into neurons o Want to look at neural plate differentiation-> definitive ectoderm, proliferating and forming lots and lots of layers, add growth factors to stem cells that are known to cause proliferation -> can study those process o Can look at signalling pathways that happen, what cells do how they migrate o Can look at how the nervous system gets patterned -> dorsal patterning growth factors and turn them into sensory neurons ▪ Can understand not just how neurons develop but how sensory neurons develop ▪ If there were problems with sensation, that information can help understand some of the pathological occurring ▪ Same thing can be done for dorsal patterning turning them into motor neurons, motor neuron development and disease. Workshop Notes  Bilateral = paired structured (on body’s left/right) Unilateral = one on one side of the body Ipsilateral = two structures being compared on the same side of the body Contralateral = two structures compared on opposite sides of the body Practical Notes General, identifiable descriptions of organs Heart: size of a large apple/fist, shaped like a pear or upside down egg (rounder top and pointier bottom), marbled texture like a steak Brain: looks like a wrinkled walnut, soft pinkish cauliflower, consistency like jelly/tofu Lung: spongy balloon, pinkish-grey, tree branches with leaves = bronchial tree Stomach: deflated ballon, bagpipe, rubber hot water, soft wrinkled leather pouch Kidney: beans, size of a smartphone, rubbery Large intestine: long bumpy tube (coiled garden hose), upside down horseshoe, series of linked sausages, bumpy accordion Small intestine: long tightly coiled garden hose, bundle of cooked spaghetti Pancreas: lumpy banana, fish fillet (wider head, narrow tail), long pine cone Gallbladder: small green pear, deflated balloon Muscles, nerves, and vessels  ARTERY Description - Firm and elastic - Thick muscular walls - Thick rubber hose / springy thick rubber cord - Larger than veins and nerves - Red appearance Location in relation to Close to tissues and organs (to supply oxygen). other nearby structures VEIN Description - Softer, thinner, flexible - Blue appearance - Rubber tube, soft cord, flexible straw Location in relation to Carry deoxygenated blood to the heart, located running parallel to arteries, other nearby structures typically closer to skins surface and sometimes bile ducts. NERVE Description - Smooth  - Rope-like Location in relation to Transmit signals between brain, spinal cord, and body, often running other nearby structures alongside structures including muscles, blood vessels, and bones. Muscles Nerves Bone Joints