Sem 1 Anatomy and Physiology Revision Notes PDF

**[Sem 1 Anatomy and Physiology Revision Notes]** **[Lecture 1 -- Levels of Organisation]** Integumentary system = Hair, epidermis and associated glands, nails. Appendicular muscles = support, move and brace limbs. Axial muscles = Head, neck, core. CNS = brain, spinal cord. PNS = peripheral ne...

**[Sem 1 Anatomy and Physiology Revision Notes]** **[Lecture 1 -- Levels of Organisation]** Integumentary system = Hair, epidermis and associated glands, nails. Appendicular muscles = support, move and brace limbs. Axial muscles = Head, neck, core. CNS = brain, spinal cord. PNS = peripheral nerves. [Endocrine system:] - Pineal gland -- Middle of brain/epithalamus - Pituitary gland -- Base of the brain, behind the nose bridge. - Thyroid gland -- Neck. - Parathyroid gland -- Neck. - Pancreas -- Abdomen. - Adrenal gland - Kidney - Ovaries in females. - Testes in males [Lymphatic system:] - Lymph nodes -- Filter out waste products. - Thymus -- Makes T lymphocytes. - Spleen -- Controls the level of blood cells. - Lymphatic vessel. [Respiratory:] 1. Nasal cavity. 2. Sinuses. 3. Pharynx. 4. Larynx. 5. Trachea. 6. Bronchi. 7. Lung. - Diaphragm. [Digestive system:] - Salivary gland -- Releases saliva which contains amylase which breaks down starches. - Pharynx -- Passageway. - Oesophagus -- Muscular tube that carries food. - Liver -- Processes blood, breaking down nutrients and chemicals. - Stomach -- Contains hydrochloric acid and enzymes for digestion. - Gallbladder -- Stores bile, which is produced by the liver to help digest fats. - Large intestine -- Absorbs water and salts from undigested food. - Small intestine -- General absorption and digestion. - Anus. [Urinary system:] - Kidney -- Filters blood, removing waste and extra fluid. - Ureter -- Carries urine from kidneys to bladder. - Urinary bladder -- Stores urine, - Urethra -- Excretes urine. [Reproductive System:] Male: - Ductus deferens. - Seminal vesicles. - Prostate gland. - Urethra. - Penis. - Epididymis. - Testis. - Scrotum. Females: - Mammary gland. - Uterine tube. - Ovary. - Uterus. - Vagina. - External genitalia. [Anatomical landmarks:] - Cephalon = head - Axilla = armpit - Brachium = arm - Antebrachium = forearm - Carpus = wrist - Pollex = thumb - Digits = fingers or toes - Tarsus = ankle - Hallux = great toe - Manus = hand - Umbilicus = navel = belly button - Mamma = breast - Thoracis = thorax = chest - Nasus = nose - Cervicis = neck - Dorsum = back - Olecranon = back of elbow - Loin = lumbar - Popliteus = back of knee - Calf = sural - Calcaneus = hell of foot - Planta = sole of foot [Directional terms:] Medial = toward midline of the body. Lateral = away from midline of the body. Proximal = closer to the centre of the body or point of origin e.g. shoulder is proximal to the arm. Distal = further away from the centre of the body or the point of origin e.g. fingertips are distal to the arm. Superior = toward the head end (top) of the body). Inferior = away from the head / toward the foot end (bottom) of the body. Cranial = toward the head. Caudal = toward the tail end of the body. Dorsal/Posterior = back side of body. Ventral/Anterior = front side of body. [Body Cavities] - Dorsal = contains brain and spinal cord. - Ventral = contains thoracic, abdominal, and pelvic organs. **[Lecture 2 -- The Nervous System]** [CNS] - Brain and spinal cord. - Integrates and coordinates the processing of sensory data and the transmission of motor commands. Coordinated higher functions. [PNS] - Includes all neural tissue outside CNS. - Delivers sensory info to CNS. Carries motor commands to peripheral tissues and systems. [Neurons] Anaxonic neurons: - Found in brain and special sense organs. - Very small. - No anatomic features that distinguish dendrites from axon. Bipolar neurons: - 2 processes, 1 dendrite and 1 axon, with the cell body between them. - Occur in special sense organs. Unipolar: - Dendrites and axon are continuous, cell body lies off to one side. - Most sensory neurons of the PNS. Multipolar: - 2 or more dendrites and 1 axon. - Most common neurons in CNS. - All motor neurons that control skeletal muscle. [The Spinal Cord] - Major passageway of sensory and motor impulses to/from brain. - Integrates information on its own and controls spinal reflexes and automatic motor responses. - 31 segments. Each contains a pair of dorsal root ganglia, containing the cell bodies of sensory neurons. - Dorsal roots bring sensory information to spinal cord. - A pair of ventral roots contain axons of motor neurons. - Sensory (dorsal) and motor (ventral) roots are bound together into a single spinal nerve. Special anatomy of spinal cord: - Grey matter contains cell bodies and neuroglia (glial) cells. - White matter contains myelinated and unmyelinated axons. - Horns -- projections of grey matter. **[The Brain]** - Higher brain -- neocortex (cerebral cortex), which sets us apart from all other animals. Frontal lobe consists of: - Primary motor cortex (precentral gyrus). - Somatic motor association area (premotor cortex). - Prefrontal cortex. Temporal lobe consists of: - Auditory association area. - Auditory cortex. - Olfactory cortex. Occipital lobe consists of: - Visual association area. - Visual cortex. Parietal lobe consists of: - Primary sensory cortex (postcentral gyrus). - Somatic sensory association area. [Brain protection and support] Physical protection: - Bones of cranium. - Cranial meninges. - Cerebrospinal fluid. Biochemical isolation: - Blood-brain barrier; isolation of CNS from general circulation through variation in permeability of CNS capillaries. The cranial meninges have 3 layers: - Dura mater. - Arachnoid mater. - Pia mater. - Continuous Cerebrospinal fluid: - Surrounds all exposed CNS surfaces. - Interchanges with interstitial fluid of brain. - Cushion, support, transport of nutrients and chemical messengers and waste products. **[The Cranial Nerves]** 1. Olfactory (sensor) -- Receptor - olfactory epithelium in nasal cavity. 2. Optic (sensor) -- Receptor - retina. 3. Oculomotor (motor) -- Controls eye movement. 4. Trochlear (motor) -- Controls eye movement. 5. Trigeminal (sensor and motor) -- Sensation in eyes, nose, forehead, structures of the mouth. Motor control of the chewing muscles. 6. Abducens (motor) -- Motor control of lateral movement of the eye. 7. Facial (sensor and motor) -- Sensation of tase. Motor control of facial expressions, tear gland, and salivary glands. 8. Vestibulocochlear (sensor) -- Balance and hearing. 9. Glossopharyngeal (sensor and motor) -- Sensation of taste. Motor control of pharyngeal muscles for swallowing. 10. Vagus (sensor and motor) -- Wide roles abdomen and thorax, key of CV system. 11. Accessory (motor) -- Motor control of the neck and upper back. 12. Hypoglossal (motor) -- Motor control of muscles in tongue. **[Lecture 3 -- Action potentials, Synapses, and Neurotransmitters]** - Resting membrane potential = -70mV. - Extracellular fluid contains high concentrations of Na^+^ and Cl^-^. Intracellular fluid contains high concentrations of K^+^ and negatively charged proteins (pr^-^) Passive movement: - Chemical concentration gradient: move K+ out cell and Na+ into cell. - K+ moves out cell faster than Na+ can move in. - Electrical gradient: positive charged outer membrane surface repels K+ ions. - At same time, negative charged inner membrane attracts positive Na+. - Chemical gradient is stronger than electrical repelling force. - K+ still moves. - Net loss of positive ions. *Notes for resting potential, changes in membrane potential (depolarisation), and repolarisation not required.* [Graded Potentials] - Also called local potentials. - Only affect limited portion of cell membrane -- cannot spread far. - Affected area too small to have an effect on the activities of cells. - Produced by any stimulus that opens a gated channel. - Occur in the membranes of all cells in response to stimuli. Step 1: - Resting membrane exposed to chemical. - Sodium channel opens, Na+ enter the cell. - Membrane potential rises, depolarisation occurs. Step 2: - Movement of Na+ through channel produces local current. - Depolarises nearby cell membrane (graded potential). - Change in potential is proportional to the stimulus. Step 3: - When stimulus is removed, membrane potential returns to normal -- repolarisation. - Graded potentials can influence operations in distant portions of the cell only if they lead to the production of an action potential. [Action Potentials] *Notes on definitions etc not required.* Generation of an action potential: - Step 1 = Depolarisation of the membrane to threshold. - Step 2 = Activation of Na+ channels and rapid depolarisation. - Step 3 = Inactivation of Na+ channels and activation of K+ channels. - Step 4 = Brief hyperpolarisation. Return to normal permeability. - Return to resting potential. [Continuous Propagation of an Action Potential] - Step 1 = Action potential in segment one depolarises to +30mV. - Step 2 = Local current: Na+ spread away from channel. Depolarises second segment to threshold. - Step 3 = Second segment develops action potential. First segment enters refractory period. - Step 4 = Local current depolarises next segment. Cycle repeats. Saltatory propagation: - Continuous propagation cannot occur in a myelinated axon. - Depolarisation only occurs at the nodes. - The action potential 'jumps' from node to node. - Faster than continuous propagation. [Synapses and Neurotransmitters] *Notes of synapses not necessary.* Excitatory neurotransmitters: - Cause depolarisation of postsynaptic membranes. - Promote action potentials. Inhibitory neurotransmitters: - Cause hyperpolarisation of postsynaptic membranes. - Suppress action potentials. **[Lecture 4 -- Tissues]** [Epithelial Tissue] - Layers of cells which forms linings, membranes , and glands. - Classified according to: - Number of layers (simple or stratified) - Shape (squamous, cuboidal, columnar, or transitional). [Squamous Epithelia] Simple Squamous: - Functions = Reduces friction. Absorption. Secretion. - E.g. linings of blood vessels and alveoli. Stratified Squamous: - Functions = Physical protection against abrasion, pathogens, and chemical attack. - E.g. skin. [Cuboidal Epithelia] Simple Cuboidal: - Functions = Limited protection. Secretion. Absorption. - E.g. glands and ducts. Stratified Cuboidal: - Functions: Protection. Secretion. Absorption. - E.g. lining of some ducts (rare). [Transitional Epithelium] - Functions: Permits expansion and recoil after stretching. - E.g. urinary bladder. [Columnar Epithelia] Simple Columnar Epithelium: - Functions: Protection. Secretion. Absorption. - E.g. lining of stomach and intestine. Pseudostratified Ciliated Columnar Epithelium: - Functions: Protection. Secretion. Move mucus with cilia. - E.g. lining of nasal cavity, trachea, and bronchi. Stratified Columnar Epithelium: - Function: Protection. - E.g. Small areas of the pharynx. [Exocrine Glands] - Classified according to: - Shape (tubular, coiled, branched, alveolar). - Number of ducts (simple/one, or compound/multiple). [Connective Tissue] Areolar tissue: - Supports/protects. - Contains: - Cells e.g. fibroblasts, adipocytes, macrophages. - Fibres e.g. collagen, reticular, elastic. - Ground substance e.g. fluid (blood or lymph), gel (cartilage), mineral (bone). [Loose Connective Tissues] Adipose Tissue: - Locations: Deep to the skin especially at sides, buttocks, breasts. Padding around eyes and kidneys. - Functions: Provides padding and cushions shocks. Insulates. Stores energy. Reticular Tissue: - Locations: Liver, kidney, spleen, lymph nodes, and bone marrow. - Functions: Provides supporting framework. [Dense Connective Tissue] Dense Regular Connective Tissue: - Functions: Provides firm attachment. Conducts pull of muscles. Stabilises relative positions of bones. - E.g. Tendons, ligaments. Dense Irregular Connective Tissue: - Functions: Provides strength to resist forces applied from many directions. Helps prevent overexpansion of organs such as the urinary bladder. - E.g. Capsules of visceral organs, nerve and muscle sheaths, dermis. Elastic Tissue: - Functions: Stabilises. Cushions shocks. Permits expansion and contraction. - E.g. Between vertebrae of the spinal column, in blood vessel walls. [Cartilage] Hyaline Cartilage: - Functions: Provides stiff but somewhat flexible support. Reduces friction between bony surfaces. - E.g. Between tips of ribs and bones of sternum, covering bone surfaces at synovial joints, forms part of nasal septum. Elastic Cartilage: - Functions: Provides support but tolerates distortion without damage and returns to original shape. - E.g. Auricle of external ear. Fibrocartilage: - Functions: Resists compression. Prevents bon-to-bone contact. Limits movement. - E.g. Pads within knee joint, intervertebral discs. [The Fasciae] - Superficial Facia: Between skin and underlying organs. Areolar tissue and adipose tissue. - Deep Fascia: Forms a strong, fibrous internal framework. Dense connective tissue. - Subserous Fascia: Between serous membranes and deep fascia. Areolar tissue. [Muscle Tissue] - Skeletal, cardiac, smooth. [Neural Tissue] [Summary] - Epithelial. - Simple, stratified. - Squamous, cuboidal, columnar. - Glands. - Connective. - Contain cells, ground substance, and fibres. - Types: - Fluid (blood, lymph). - Loose connective tissue e.g. adipose, reticular. - Dense connective tissue (dense regular, dense irregular, elastic). - Cartilage (hyaline, elastic, fibrocartilage). - Bone. - Muscle. - Skeletal. - Cardiac. - Smooth. - Neural. - Neurons. - Neuroglia. **[Lecture 5 -- Bone Physiology]** [Functions of the Skeletal System] - Support against gravity. - Leverage for muscle action. - Protection of soft internal organs. - Storage. - Calcium, phosphorus. - Fat. - Blood cell production. [Bone classification by shape] - Flat = Internal and external table separated by diploe e.g. parietal bone. - Long = Longer than they are wide e.g. humerus. - Short = Similar width to length e.g. carpal bones. - Irregular = Complex shapes e.g. vertebra. - Sutural = Between skull bones. - Sesamoid = Small, develop in tendons e.g. patella. [Features of a typical long bone] - Diaphysis (shaft). - Compact/dense bone. - Medullary cavity. - Epiphyses (ends). - Trabecular (spongy) bone. - Articular cartilage. [Bone (Osseous) Tissue] - Ground substance. - 2/3 of bone matrix. - Minerals. - Protein. - 1/3 of bone matrix. - Most abundant protein type I collagen fibres. - Bone cells. - Only 2% of bone mass. - Mesenchymal stem cells osteoblasts osteocytes - Osteoclasts. [Osteoblasts ("bone builder")] - Immature bone cell. Secretes matrix proteins. [Osteocytes ("bone cells")] - Mature bone cell that maintain the bone matrix.  [Osteoclasts] - Multinucleate cell that secretes acids and enzymes to dissolve bone matrix. [Microscopic structure of compact bone] - Osteon. - Basic functional unit. - Columnar. - Strong in long axis. - Central canal - Tunnel for blood vessels. - Lamellae. - Concentric layers of matrix. - Lacunae. - Contain cells: osteocytes. [Microscopic features of trabecular (spongy) bone] - No osteons. - Trabeculae. - Arches, rods, plates of bone. - Branching network. - Strong in many directions. - Red marrow. - Between trabeculae. - Forms red blood cells. - Provides nutrients to osteocytes. - Yellow bone marrow. - Found in medullary cavity. - Stores fat. [Bone structure and loading patterns] - Osteon structure of compact bone provides strength in long axis. - Trabecular bone provides strength in a range of directions. - Trabeculae align according to habitual loading patterns. [Periosteum] Membrane outside bone. - Outer (fibrous) layer. - Collagen fibres continuous with bone, ligaments, tendons, joint capsule. - Inner (cellular) layer. - Also contains lymphatic. [Endosteum] Membrane lining bone. - Incomplete cellular layer. - Lines. - Medullary cavity. - Central canals. - Trabeculae. [Bone tissue summary] - Skeleton provides support, protection, and leverage for movement. Also stores calcium and is the location of blood cell production. - Long bones provide leverage, flat bones provide protection, short bones allow subtle transfer of forces, irregular bones have a variety of roles. - Bone consists of minerals, proteins including collagen fibres, and cells; osteoblasts, osteocytes, and osteoclasts. - Compact bone has a denser and more organised structure providing strength in the long axis. Trabecular bone is less dense and more rapidly turned over. - The periosteum consists of a fibrous and cellular layer whilst the inner endosteum has just a cellular layer. [Bone Formation and Growth] Ossification = Formation of/conversion into bone. - Intramembranous ossification. (Intra = inside). - Flat bone formation. - Endochondral ossification. (Endo = inner). (Chondr = cartilage). - Formation from cartilage model. - Appositional bone growth. - Growth in width. Intramembranous ossification: 1. Mesenchymal cells differentiate into osteoblasts. 2. Ossification forms spicules of bone. 3. Trabecular bone formed. 4. Remodelled into compact bone. Endochondral ossification: 1. Chondrocytes within calcifying matrix enlarge then die. 2. Osteoblasts cover the shaft in a thin layer of bone. 3. Blood vessels and osteoblasts penetrate to form primary ossification centre. 4. Primary ossification centre enlarges. 5. Secondary ossification centres formed at epiphyses. Appositional bone growth: [Requirements for normal bone growth] - Minerals -- calcium and phosphate. - Vitamins -- Vitamin D3 and others. - Hormones -- Growth hormone, sex hormones, thyroid hormone, etc. - Loading. [Bone remodelling and homeostasis] - Continuous breakdown and reforming of bone tissue. - Resorption by osteoclasts, formation by osteoblasts. - Adaptation to loading. - Osteocytes detect forces in bone. - Calcium homeostasis. - 99% of calcium stored in bone. - Hormones control storage/release. - PTH stimulates bone resorption to release calcium. - Calcitonin stimulates bone formation to store calcium. [Fracture repair] 1. Bleeding and formation of clot (fracture haematoma). 2. Formation of external callus (cartilage) and internal callus (spongy bone). 3. External callus replaced by bone. Internal callus unites broken ends. 4. Initial swelling eventually remodelled. [Bone formation, remodelling, and healing -- summary] - The majority of bones form through endochondral ossification. - Starts with a cartilage model; primary and secondary centres of ossification produce bone separated by epiphyseal (growth) plates. - Flat bones form through intramembranous ossification. - Bones increase in width through appositional growth. - Bone remodelling allows calcium storage/release and adaptation to mechanical requirements. - Requires adequate calcium, vit D, and mechanical loading. - Inadequate nutrition, inactivity, and oestrogen deficiency can contribute to low bone density. - Fracture healing involves formation of a fracture haematoma, which is replaced by external and internal calluses, that are gradually replaces by bone. **[Lecture 6 -- Skeletal Anatomy]** [Skeletal Terminology] Projections: - Process -- Any projection/bump. Processes where tendons/ligaments attach: - Trochanter -- large rough projection. - Tuberosity -- smaller rough projection. - Tubercle -- small round projection. - Crest -- ridge. - Spine -- pointed process. Articulating surfaces: - Head -- expanded epiphysis. - Condyle -- smooth and rounded. - Facet -- small and flat. Openings: - Foramen -- passageway for blood vessel or nerve. - Canal -- passageway through bone.  [**Axial Skeleton** (torso, head)] [The Cranium] - Frontal bone -- forehead, superior surface of orbits. - Parietal bones -- sides, roof. - Temporal bones -- sides, base. - Occipital bone -- foramen magnum. - Sphenoid bone -- bridge between cranial and facial bones. - Ethmoid bone -- cribriform plate / nasal septum. Facial bones -- functions: - Supporting cavities and sense organs (eye, olfactory). - Attachment of muscles/structures for mastication (chewing), speech, and facial expression. - Protection. - Maxillary bones. - Zygomatic bones -- zygomatic arch (with temporal bones). - Mandible. - Nasal bones. - Nasal conchae. - Nasal septum. Paranasal sinuses: 06\_13ParanasalSinuses\_L [Vertebral Column] 26 bones of the spine. - 7 cervical. - 12 thoracic. - 5 lumbar. - Sacrum. - Coccyx. - Curves help alignment of weight. Vertebral anatomy: - Body. - Weightbearing. - Articulate with bodies above/below. - Separated by intervertebral discs. - Arch. - Consists of pedicle and lamina. - Supports transverse and spinous processes. - Surrounds vertebral foramen, protects spinal cord. - Spinous process. - Muscle attachment. - Transverse process. - Muscle attachment. - Articular processes. - Articular facets. - Articulate with vertebrae above/below. Regional variation in vertebral anatomy: Cervical -- - Oval body. - Transverse foramina. - Bifid (split) spinous process. Thoracic -- - Heart-shaped body. - Facets for articulation with ribs. - Long, inferiorly directed spinous process. Lumbar -- - Massive (heaviest loading). - Blade-like transverse processes.  Vertebral column: The atlas and axis - Atlas -- articulates with occipital condyles. - Axis -- articulates with atlas. [Thoracic Cage] Functions: - Protection of thoracic contents. - Allowing expansion and contraction for ventilation. Components: - Sternum. - Ribs. - Seven pairs of true ribs. - Cartilaginous joint with sternum. - Five pairs of false ribs. Ribs: - Curved flat bone. - Head articulates with vertebral body. - Tubercle articulates with transverse process of vertebra. - Costal cartilages articulate with sternum. [**Appendicular Skeleton** (limbs)] [Pectoral Girdle] Functions: - Enable versatile movement. - Articulation for arm. Components: - Clavicles. - Scapulae. - Acromion. - Scapular spine. - Glenoid cavity. [Humerus] - Head articulates with scapula. - Several sites of muscle attachment. - Distal condyles articulate with forearm. [Radius and Ulna] Radius: - Lateral (thumb side). - Head articulates with humerus. - Distal end participates in wrist joint. Ulna: - Trochlear notch articulates with humerus. - Olecranon forms point of elbow. Forearm pronation:  [Bones of Wrist and Hand] - Two rows of carpal bones. - Proximal row articulates with radius. - Distal row articulate with metacarpals. - Metacarpals. - Support palm. - Numbered I (thumb) to V. - Phalanges (finger bones). - Articulate with metacarpals. - Three phalanges per finger. - Proximal, middle, distal. - Two phalanges per thumb. - Proximal, distal. [Appendicular Division -- Pelvis] Functions: - Support. - Articulation of the leg. Consists of: - Os coxae (coxal bones). - Sacrum. - Coccyx. Os coxae: - Coxal bone formed by fusion of: - Ilium. - Ischium. - Pubis. - Features include: - Iliac crest. - Acetabulum. - Ischial tuberosities. Pelvis -- sex differences:  [Femur] - Head. - Neck. - Greater trochanter. - Shaft. - Condyles. [Tibia and Fibula] Bones of the lower leg. - Features of the tibia: - Medial and lateral condyles. - Articulate with femur. - Medial malleolus. - Distal articular surface. - Participates in ankle joint. - Features of the fibula: - Articulation of head with tibia. - Lateral malleolus. - Distal articular surface. - Participates in ankle joint. [Ankle and Foot] Ankle: - Seven tarsal bones including: - Talus. - Joint with tibia and fibula. - Calcaneus (heel bone). - Major load-bearing. Foot: - Metatarsal bones. - Numbered I to V. - Phalanges (toes). - Hallux. - Proximal and distal. - Other toes. - Proximal, middle, and distal.  Foot Curvature: **[Lecture 7 -- Articulations/Joints]** Articulations (joints) -- Where two or more bones connect. - Functions = allowing movement, stability. - Classification of joints = functional, structural. [Joint classifications -- Functional] Functional classifications describe joints in terms of the amount of movement: - Synarthrosis = immovable joint. - Amphiarthrosis = slightly movable joint. - Diarthrosis = freely moveable joint. *Notes on angular movements (flexion/extension, abduction/adduction, circumduction, rotation including pronation and supination) not necessary.* Special movements of the foot: - Inversion = twist sole medially. - Eversion = twist sole laterally. - Dorsi flexion = flexion at ankle (raise toes). - Plantar flexion = extension at ankle (pointing toes). [Joint classifications -- structural] - Structural classifications describe joints according to composition of joint structures. - Bony fusion. - Fibrous. - Cartilaginous. - Synovial. [Bony Joints] **Type** **Functional classification** **Description** **Example** ------------ ------------------------------- ----------------- ------------------------------------------- Synostosis Synarthrosis Articulating Joint between left and right frontal bone [Fibrous Joints] **Type** **Functional classification** **Description** **Example** ------------- ------------------------------- -------------------------------------------------------------- -------------------------------- Suture Synarthrosis Articulating bones interlock and attached by collagen fibres Sutures in cranium Gomphosis Synarthrosis Tooth fits in socket attached by ligament Joints between teeth and jaws Syndesmosis Amphiarthrosis Bones connected by ligament Joint between tibia and fibula [Cartilaginous Joints] **Type** **Functional classification** **Description** **Example** --------------- ------------------------------- ---------------------------------------- ------------------ Synchondrosis Synarthrosis Bones attached by cartilage Costal cartilage Symphysis Amphiarthrosis Bones separated by fibrocartilage disk Pubic symphysis [Synovial Joints] **Type** **Functional classification** **Description** **Example** ---------- ------------------------------- ----------------------------------------------- ------------------------------------------------- Synovial Diarthrosis Cartilage, synovial, fluid, and joint capsule Typically found at ends of long bones e.g. knee Features of a typical synovial joint: A diagram of a knee joint Description automatically generated [Joint Accessory Structures] - Cartilages = Cushions the joint e.g. meniscus -- fibrocartilage pad in knee. - Fat pads = Superficial. Provide protection. - Ligaments = Support, strengthen joint. - Tendons = Attach to muscles. Help support joint. - Bursae = Pockets of synovial fluid. Cushion where tendons or ligaments rub. [Types of synovial joint according to articulating bone shape] **Type** **Movement** **Example** ----------------- ---------------------- ------------------------ Gliding Slight Claviculo-sternal Hinge Monoaxial Elbow Pivot Monoaxial (rotation) Atlanto-axial Condylar Biaxial Radiocarpal Saddle Biaxial First carpo-metacarpal Ball and socket Triaxial Shoulder [Factors that affect synovial joint function] - Join and accessory structures - Shapes of articulating bones. - Joint capsule, ligaments. - Menisci. - Tendons and muscle crossing joint. - Other bones, muscles, fat pads. Limiting movement increase stability (and vice versa). [Joint structure and classification -- summary] - Functional classifications: - Synarthrotic -- no movement. - Amphiarthrotic -- slight movement. - Diarthrotic -- variety of movements. - Structural classifications: - Bony fusion (synostosis). - Fibrous (suture, gomphosis, syndesmosis). - Cartilaginous (synchondrosis, symphysis). - Synovial -- subclassified into gliding, hinge, pivot, condylar, saddle, ball and socket. - Structure of synovial joint: - Articular cartilage, joint capsule, synovial membrane, synovial fluid. - Accessory structures (e.g. ligaments, bursae, fat pads, menisci). [Intervertebral Articulations (C2 to L5)]  Damage to intervertebral discs: A diagram of the spine Description automatically generated  [Shoulder (glenohumeral) joint] A diagram of the shoulder joint Description automatically generated [Hip (coxal) joint]  [The Elbow] A diagram of a human elbow Description automatically generated [The Knee]  A diagram of the muscles of the knee Description automatically generated [Injuries] - Sprain -- Tearing of ligament fibres. - Dislocation (luxation) -- Articulating surfaces displaced. Damages articular cartilage, ligaments, joint capsule. - Subluxation -- Partial dislocation. [Joint Diseases] Osteoarthritis: - Damage to articular cartilage and underlying bone. - More common with age, obesity, and injury. - Inflammatory condition. Rheumatoid arthritis: - Autoimmune condition. - Inflammation of articular cartilage. Gouty arthritis: - Deposition of crystals in joint as a result of metabolic disorder (gout). **[Lecture 8 -- Skeletal Muscle]** Muscle:  Muscle fibre: A diagram of a cross section of a body Description automatically generated [Sarcomere Structure] - Each myofibril is composed of thousands of sarcomeres. - Joined in series and parallel to one another. - Sarcomeres are the functional units of muscle. - Made up of many myofilaments.  Actin (thin filament): - Actin subunits in double helical strands. - Tropomyosin interacts with actin and covers binding sites where thick filament can bind. A diagram of a thin filament Description automatically generated Myosin (thick filament): Two sub-units: - S1 -- Globular head. - S2 -- Flexible region and tail.  Structural proteins to be aware of: - Titin, Nebulin, and Desmin. [Sliding-Filament Mechanism] - During contraction filaments slide past each other. - Each of the two filaments remain relatively unchanged in length despite changes in gross muscle length. Sarcoplasmic Reticulum: - Interconnecting tubules surrounding myofibrils. - Regulates intracellular levels of calcium. - Stores calcium and releases on stimulation to allow contraction. The Cross-Bridge Cycle: 1. Action potential arrives. 2. Ca++ released from sarcoplasmic reticulum. 3. Ca attaches to troponin. 4. Tropomyosin moves, uncovering binding sites. 5. Hydrolysis of ATP changes angle of the myosin head. Cross-bridge formed. 6. P~i~ released from myosin head changes angle of the myosin head. (Power stroke). 7. Myosin head picks up another ATP and bond with actin is released. 8. Repeats until Ca++ or ATP levels drop.  Length-Tension Relationship: A. Filaments overlapped, not able to generate tension. B-C) Muscle stretches, no longer butting against Z line, able to produce tension (to optimal point). D\) If the fibre is lengthened further, less overlap between myosin and actin means less opportunity to develop tension. Force-Velocity Relationship: - Force during shortening \< isometric force: - The faster the movement, the less time myosin heads have to attach to binding site. - Force during lengthening \> isometric force: - Compliant portion of myosin stretched further than during isometric force. - Forcible detachment of myosin heads with stretch. [The Motor Neuron] - Motor neuron = nerve cell. - Motor unit = a single motor neuron and all of the fibres it innervates. - Gross movements require 2-3000 fibres per motor unit. - Fine movements require 2 or 3 fibres per motor units. A single Node of Ranvier: Diagram of a structure with red lines and white text Description automatically generated At rest:  - At rest there is more Na+ outside than inside the axon. When a nerve impulse arrives: - Action potential arrives and Na+ channels open up. - Na+ enters the axon. Inside of axon becomes more positive: A diagram of a structure Description automatically generated - Increased Na+ within the axon causes the exposed part of the axon between the myelin sheaths to depolarise and Na+ gates to close. Inside of axon becomes less positive:  - When membrane potential reaches +30mV, K+ gates open. - K+ leaves the axon and the inside of the axon becomes less positive. - Repolarisation. [Neuromuscular Junction] - Where motor neuron meets the muscle fibre. - Motor end plate = pocket formed around motor neuron by sarcolemma. - Synaptic cleft = short gap between neuron and motor end plate. - Acetylcholine is released from the motor neuron, resulting in depolarisation of motor end plate (muscle fibre). [Skeletal muscle control] - Efferent neurons -- Neurons that send impulses from the central nervous system to your limbs and organs (e.g. the muscles). - Afferent neurons -- Neurons that carry nerve impulses from sensory receptors or sense organs toward the central nervous system. A diagram of a muscle Description automatically generated [Golgi Tendon Organs] - Senses tension in the tendon when the muscle contracts. - Has an inhibitive (negative) afferent neuron. - When excessively large forces are generated, feedback from GTO causes activation of muscle to decrease -- protective.  [Muscle Spindles] - Highly specialised encapsulated muscle fibres (intrafusal) positioned parallel to normal muscle fibres (extrafusal). - Sensitive to changes in muscle length. - Afferent neuron wraps around the muscle spindle. - Efferent neuron (Gamma) cause muscle spindles to contract to maintain tension in middle of the fibres. - Hence if muscle is stretching rapidly, a vigorous contraction is caused to precent overstretching. **[Lecture 9 -- The Brain and Special Senses]** [Smell -- Olfaction] - Provided by paired olfactory organs. - Located in the nasal cavity, on either side of nasal septum, inferior to the cribriform plate of ethmoid bone. - Olfactory organs consist of olfactory epithelium and olfactory glands. The Process of Olfaction: 1. When breathing in, air swirls within nasal cavity. 2. Upon reaching the olfactory organs, lipid- and water-soluble chemicals diffuse into the mucus before stimulating olfactory receptors. 3. Dissolved chemicals interact with receptors -- odorant binding proteins -- on cilia surfaces. (*cilia attached to each receptor cell extends into mucus*). 4. (*Odorants = chemicals that stimulate olfactory receptors*). Binding of odorants changes permeability of receptor membrane action potentials. 5. Info is relayed to CNS, where the smell is interpreted. Many olfactory receptor cells packed into a small area. Olfactory Pathways: - Bundles of axons (cranial nerve I) penetrate the cribriform plate of ethmoid bone to reach the olfactory bulb. - Axons leaving each olfactory bulb travel along olfactory tract to the olfactory cortex of cerebrum, the hypothalamus, and portions of limbic system. [Taste] Taste/Gustatory Receptors: - Located over superior surface of the tongue and adjacent pharynx and larynx. - Taste receptors and specialised epithelial cells form sensory structures -- taste buds. - Taste buds lie along the sides of epithelial projection -- papillae. There are 3 types of papillae: - Filiform (no taste buds). - Fungiform (\~5). - Circumvallate (\~100).  - Each taste bud contains slender sensory receptors -- gustatory cells -- plus supporting cells. - Each gustatory cell extends slender microvilli into surrounding fluids through a taste pore. Taste sensations: - Water receptors (pharynx). - Umami (savoury). - Bitter. - Sour. - Salty. - Sweet. Taste Mechanisms: - Dissolved chemicals contacting taste hairs stimulate a change in the membrane potential of the taste cell, resulting in an action potential in the sensory neuron. Taste Pathways: - Taste buds are monitored by 3 cranial nerves: facial, glossopharyngeal, vagus. - Sensory fibres of the different nerves synapse within a nucleus in the medulla oblongata. - Axons of the postsynaptic neurons synapse in the thalamus. [Vision] Anatomy of the Eye: - Located in the orbit, along with -- extrinsic eye muscles, lacrimal gland, cranial nerves, blood vessels, and fat. A diagram of the human body Description automatically generated Mechanisms of Vision: - Light enters the eye and is refracted at the cornea and lens. - Refraction = the alteration/bending of light when it travels from one medium to another. - Greatest refraction occurs at the cornea. - Light is absorbed at the retina by the photoreceptors (rods and cones). - Each eye contains \~ 100 million rods and \~ 5 million cones. - Cones predominate in central vision; rods predominate in the periphery. The Process of Seeing: - Light interacts with light-sensitive molecules -- photopigments -- in the photoreceptors. - Photopigments consist of Rhodopsin, made of opsin and retinal. - In the presence of light, rhodopsin splits, altering the flow of electrical current. Visual Pathways: - Two optic nerves reach the diencephalon at the optic chiasm. - Here, half of the nerve fibres from each eye cross over to reach the thalamus on the opposite side of the brain. - Nuclei in the thalamus relay visual information to reflex centres in the brain stem as well as to the visual cortex of the cerebrum. [Hearing] - The senses of hearing and equilibrium are provided by the inner ear, a receptor complex located in the temporal bone of the skull. - The receptor mechanism for both of these senses is the same. - The receptors, or hair cells, are simple mechanoreceptors. The Middle Ear: - Air-filled cavity. - Separated from the ear canal by the tympanic membrane. - Contains auditory ossicles: malleus, incus, and stapes. The Inner Ear: - Receptors for hearing and balance lie within the membranous labyrinth, which contains two fluids called endolymph and perilymph. - The bony cochlea contains the cochlear duct. - Cochlear duct is sandwiched between a pair of perilymph-filled chambers. - Bony labyrinth walls are dense bone everywhere, except at 2 places -- round window (base of tympanic duct) and oval window (base of vestibular duct). The Organ of Corti: - Hair cells of cochlear duct located in Organ of Corti. - This sits above basilar membrane. - Stereocilia of hair cells in contact with tectorial membrane. The Process of Hearing: 1. Sound waves arrive at tympanic membrane. 2. Movement of tympanic membrane causes displacement of the auditory ossicles. 3. Movement of the stapes at the oval window establishes pressure waves in the perilymph of the vestibular duct. 4. The pressure waves distort the basilar membrane on their way to the round window of the tympanic duct. 5. Vibration of the basilar membrane causes vibration of hair cells against the tectorial membrane. 6. Info about the region and the intensity of stimulation is relayed to the CNS over the cochlear branch of cranial nerve VIII.  Auditory Pathways: - Sensory neurons located in spiral ganglion monitor cochlear hair cells. - Afferent fibres form cochlear branch of vestibulocochlear nerve. - Axons of cranial nerve VIII enter the medulla oblongata and synapse at the cochlear nucleus. - Inferior colliculus. - Synapse in thalamus. - Auditory cortex of temporal lobe. [Equilibrium] The Inner Ear: - All equilibrium sensation are provided by hair cells of the vestibular apparatus -- semi-circular canals and otoliths. The Semi-Circular Canals: - Receptors respond to rotational movements. - Hair cells located in ampulla. - Crista -- raised structure in ampulla. - Stereocilia embedded in cupula. The Otoliths: - Utricle -- horizontal linear accelerations. - Saccule -- vertical linear accelerations/gravity. Equilibrium Pathways: - Sensory neurons monitor hair cells of the otoliths and semi-circular canals. - Afferent fibres form vestibular branch of vestibulocochlear nerve. - Fibres synapse neurons in vestibular nuclei. Roles of the vestibular nuclei: 1. Integrate sensory information arriving from each side of the head. 2. Relay information to cerebellum. 3. Relay information to cerebral cortex. 4. Send commands to motor nuclei in brain stem and spinal cord. **[Lecture 10 -- The Integumentary System]** Components: - Cutaneous membrane. - Accessory structures. Functions: - Protection. - Excretion. - Maintenance of body temperature. - Production of melanin and keratin. - Synthesis of vitamin D. - Sensation -- touch, pain, pressure, temperature. [The Components of the Integumentary System]  Organisation of the Epidermis: Structure and Regeneration of the Epidermis: A close-up of a structure Description automatically generated The Epidermal Ridges of Thick Skin:  [Comparison of Thick and Thin Skin] **Thick** **Thin** ------------------------- ---------------------------------------------- -------------------------------------------------------- **Location** Fingertips, palms, soles Everywhere else **Epidermal thickness** 0.6 -- 4.5mm 0.10 -- 0.15mm **Epidermal strata** Thicker strata lucidum, spinosum and corneum No strata lucidum, thinner strata spinosum and corneum **Epidermal ridges** Present -- well-developed dermal papillae Absent -- fewer and less developed dermal papillae **Hair follicles** Absent Present **Sweat glands** More numerous Fewer **Sensory receptors** More numerous Sparser Melanocytes and Keratinocytes: A diagram of melanocyte and melanocyte Description automatically generated [Skin pigment and colouration] - Carotene = Yellowish. - Melanin = Brown. Protects from UV radiation. Contributes to freckles and tan. - Blood = Contributes to pink (or blue) colouration. [The Dermis] - Supports the epidermis -- collagen and elastin fibres. - Papillary layer -- areolar tissue. - Reticular layer -- fibrous network. - Blood vessels -- papillary plexus and cutaneous plexus. - Sensory receptors.  [The Hypodermis] - Layer underneath integument. - Loose connective tissue (areolar and adipose tissue). - Connective tissue fibres interwoven with reticular layer of dermis. A diagram of the skin Description automatically generated [Summary of cutaneous membrane structure and function] Epidermis: - Stratified squamous epithelium containing keratinocytes and melanocytes. - Provides protection. - Allows regeneration. Dermis: - Connective tissues -- provides strength. - Houses blood vessels and sensory organs -- nutrient transport, touch. Hypodermis: - Loose connective tissues. - Allow movement relative to underlying structures. - Houses cutaneous plexus. [Hair Follicles and Hair] Hair functions: - Protection. - Insulation. - Sensation. Hair structure: - Medulla (core) -- contains a flexible soft keratin. - Cortex -- thick layers of hard keratin, which provide stiffness. - Cuticle thin but tough, contains hard keratin. Follicle structure: - Internal root sheath -- surrounds the hair root and deeper portion of the shaft. - External root sheath. - Glassy membrane -- thickened, clear layer wrapped in dense connective tissue sheath. - Connective tissue sheath.  [Hair Growth] During growth cycle (up to 5y): - Basal cells in hair matric divide. - Daughter cells pushed towards surface at \~0.33mm/day. - Increasingly keratinised. End of growth cycle: - Follicle becomes inactive. - Connections between hair matrix and root break down. New growth cycle: - New hair produced. - Old hair shed. [Sebaceous glands and sebaceous follicles] - Function is to secrete sebum. [The Structure and Function of a Nail] Functions: - Protection. - Limit distortion. Structure -- superficial view: A finger with the names of the same nail Description automatically generated with medium confidence Structure -- cross-sectional view and longitudinal section:  [Sweat Glands -- Apocrine and Merocrine] Functions: - Skin surface cooling. - Excretion. - Protection. [Injury and Disease] Skin cancer: - Uncontrolled cell replication. - 78% are basal cell carcinomas. - 2% are malignant melanoma (more likely to metastasise). Burns: - First degree affect epidermis -- Produce reddening. - Second degree involve some dermis damage -- Blisters may form, some scar tissue. - Third degree extend to hypodermis -- Sensory nerves destroyed. May disrupt fluid and electrolyte balance, thermoregulation, protection from infection. [Repair of Injury to the Integument]  A diagram of a human body Description automatically generated A diagram of skin anatomy Description automatically generated [Skin ageing ] Intrinsic: Reductions in e.g.; - Cell activity. - Growth factors, hormones. - Immune sensitivity. Cause e.g.; - Dermal thinning. - Wrinkling. - White hair. - Increased infection risk. - Slower healing. Extrinsic: Changes from external factors e.g.; - Sunshine exposure. - Smoking. Cause e.g.; - Increased wrinkling. - Increased skin cancer risk.