Blood Composition and Function PDF

Edith Cowan University School of Science Blood Composition Function and Composition Blood is a specialised connective tissue Serves as a number of functions: Distribution - O2, waste, hormones, nutrients Regulation - pH, temperature, fluid Protection - Clotting...

Edith Cowan University School of Science Blood Composition Function and Composition Blood is a specialised connective tissue Serves as a number of functions: Distribution - O2, waste, hormones, nutrients Regulation - pH, temperature, fluid Protection - Clotting, immunity Contains: Plasma - Non-living fluid matrix Formed elements - Living blood cells Contains fibrous proteins visible during clotting Function and Composition Overview Blood Plasma Approx. 90% water; >100 dissolved solutes Proteins - Plasma proteins; Albumin Globulins - α, β transport proteins; γ antibodies Clotting proteins - Fibrinogen; Prothrombin Non-proteins - Urea; Lactic Acid; Creatinine Nutrients - Carbs; AAs; FAs; Glycerol; Vitamins Electrolytes - Na+; K+; Ca2+; Mg2+; Cl-; HCO3- Gases - Respiratory O2 and CO2 Other - Enzymes; Antigens; Antibodies; Hormones Concentration varies constantly (Dynamic) Composition of Plasma Formed Elements Refers to ‘cellular’ elements of blood Erythrocytes, Leukocytes, Platelets Erythrocytes Red blood cells (Incomplete cells) Leukocytes White blood cells (Complete cells) Thrombocytes Platelets (Cellular discoids) Arise from red bone marrow tissue Formed Elements Overview Erythrocytes Red Blood Cells (RBCs) 7.5μm in diameter; Biconcave; Flattened Mature erythrocytes: Bound by plasma membrane Lack a nucleus Have no organelles Rich in haemoglobin (Hb) Chief function is gas transport CO2 ~20%; O2 ~ 90+% Erythrocyte Formation Formed in red bone marrow Under control of Erythropoietin Three main phases: Haemocytoblast (stem cell) Proerythroblast (committed cell) Developmental pathway Phase 1: Ribosome synthesis (erythroblast) Phase 2: Hb and Fe accumulation (normoblast) Phase 3: Ejection of nucleus (reticulocyte) Requires Vitamin B12 for stem cell division Erythrocyte Formation Overview Erythropoiesis Overview Haemoglobin Hemoglobin binds reversibly with oxygen Globin is composed of four polypeptide chains Each heme’s central iron atom binds one O2 Each Hb molecule can transport four O2 O2 loading in lungs Produces oxyhemoglobin (ruby red) O2 unloading in tissues Produces deoxyhemoglobin (dark red) CO2 loading in tissues 20% of CO2 in blood binds to Hb Haemoglobin Structure Leukocytes White Blood Cells (WBCs) 10-24μm; Spherical in nature Granulocytes (Bound granules) Neutrophils - Phagocytise bacteria Eosinophils - Kill parasitic worms Basophils - Mediators of inflammation Agranulocytes (Lack granules) Lymphocytes - Immune response via attack or antibodies Monocytes - Migratory phagocyte Chief function is defence against disease Bacteria, viruses, parasites, toxins, tumour cells Leukocyte Classes Granulocyte Formation Thrombocytes Cell fragments (Platelets) 2-4μm in diameter; Rough discs Mature platelets: Bound by a plasma membrane Lack a nucleus Age rapidly; Degenerate in 10 days if not used Rich in granules aiding clotting process (Serotonin) Chief function is blood clotting When blood vessels or their linings are injured Thrombocyte Formation Formed Elements Overview  Edith Cowan University School of Science Blood Haemostasis Haemostasis ‘Haema’ (blood) and ‘stasis’ (halt) Cessation of bleeding Also called blood clotting Framework for tissue repair In response to damaged blood vessels Three blood clotting stages: Vascular phase Platelet phase Coagulation phase Vascular Phase Vessel contraction due to injury Vasoconstriction Via smooth muscle injury Initiated by local pain receptors Allows time for clotting Endothelial cells become sticky Lasts 30 mins Platelet Phase Platelets stick to: Sticky endothelial surfaces (basal lamina) Exposed collagen fibres Platelet adhesion Attach to exposed surfaces Platelet aggregation Platelets stick to each other Seals break in vessel wall Forms a platelet plug Coagulation Phase Blood becomes a gel Prothrombin → Thrombin Fibrinogen → Fibrin Fibrin network covers plug Seals injury Forms blood clot Traps blood cells Takes 30 secs Clot Retraction Platelets contract within fibrin mesh Clot reduces in size Takes 30-60 minutes Haemostasis Overview Intrinsic and Extrinsic Pathways  Edith Cowan University School of Science Blood Tutorial (Answers) Questions List four nutrients found in plasma → Glucose, AAs, Lipids, Vitamins List two gases found in plasma → O2 and CO2 List three ions found in plasma → Na+, Cl-, HCO3- List three proteins found in plasma → Albumin, fibrinogen, globulins Questions Questions Questions Questions Which characteristic distinguishes: Erythrocytes from Leukocytes → Leukocytes have a nucleus (≠ erythrocytes) Granulocytes from Agranulocytes → Granulocytes have granules (≠ agranulocytes) What is an anticoagulant? → A substance that inhibits blood clotting What is the body’s natural anticoagulant? → Heparin (compare this to Warfarin) Questions What is benefit of the biconcave shape seen in erythrocytes? → Increased surface to volume ratio → All areas of cytoplasm close to membrane → Ability to squeeze through small vessels What is anaemia and what are the causes? → Lowered oxygen carrying capacity of the blood → Blood loss (e.g: haemorrhage) → ↓ RBC production (e.g: iron deficiency) → RBC destruction (e.g: haemolysis) Questions List the leukocytes found in blood and list their functions Granulocytes → Neutrophils (bacteria) → Eosinophils (parasitic worms, allergy, asthma) → Basophils (histamine, heparin) Agranulocytes → Lymphocytes (cell attack or via antibodies) → Monocytes (phagocytosis) Questions What type of cells are shown below? → White blood cells (leukocytes) How can function be determined based on appearance? → Granulocytes contain granules (grainy appearance) Which cells are granulocytes? → A, B and C Questions Questions Why are blood studies so important in the diagnosis of disease? → Specific changes in formed elements or plasma constituents are characteristic of certain disease states How many molecules of oxygen can a haemoglobin molecule transport? → One to four O2 per Hb molecule Questions List the functions of haemoglobin (Hb) → Hb loads oxygen in the lungs and transports it to the tissues where it is offloaded for cellular use → Hb loads carbon dioxide (waste) and transports it to the lungs where it is offloaded and exhaled to the atmosphere (maintains acid-base homeostasis) → Hb has a role in vasodilation through its release of small amounts of nitric oxide Questions Outline the role of colony-stimulating factors in the production of white blood cells → Colony-stimulating factors are cytokines (chemical messages) → They stimulate proliferation of progenitor cells → Encourage them to differentiate down a particular pathway Questions Why is a differential WBC count more valuable than a total WBC count? → Differential count = % of each WBC → ↑ or ↓ in WBCs indicates specific pathologies What does the term ‘committed cell’ refer to? → A blood cell precursor whose path of specialisation is determined (e.g: proerythroblast can only become an erythrocyte) Questions What name is given to the process of RBC production? → Erythropoiesis What hormone acts as a stimulus for this process? → Erythropoietin Why might patients with kidney disease suffer from anaemia? → When kidneys fail, they do not produce enough erythropoietin to sustain erythropoiesis in the bone marrow Questions Explain each of the processes (1-5) 5 1 2 4 3 Questions Questions How does blood doping practiced by some athletes affect erythropoietin release? → Blood doping increases the number of RBCs in the circulation and thus increases the amount of oxygen being transported → This would inhibit erythropoietin release What is a blood fraction? → Any one of the components of whole blood that has been separated from the other components (e.g: platelets, clotting factors) Questions How would you expect blood levels of bilirubin to change in a person that has severe liver disease? → It would increase because the liver’s processing functions are impaired Is an agglutinin a plasma membrane glycoprotein or an antibody in the plasma? → An agglutinin is a plasma antibody Questions Identify each of the 1 structures (A-D) Explain each of the processes (1-5) 2a A B 2b C 3 D Questions Questions Describe the constituents of a blood clot → A blood clot consists of a fibrin meshwork that traps other cells such are erythrocytes and leucocytes Explain how blood clots are removed from the body → Plasminogen is converted to plasmin, which is fibrinolytic (dissolves clots) Questions What is septicaemia? → Situation of excessive and harmful levels of bacteria or their toxins in the blood, also called blood poisoning What is a haematoma? → Accumulated clotted blood in the tissues usually resulting from injury visible as ‘black and blue’ marks or bruises, eventually absorbed naturally unless infections develop  Edith Cowan University School of Science Skeletal System Bone Composition Bone Function Bones contribute to body shape, body form, and: Support Hard framework that supports and cradles soft organs Protection Protective casing for soft organs against external forces Movement Muscles use bones as anchors and levers for movement Mineral Storage Mineral ‘reservoir’ (Ca2+, K+) for deposit and withdrawal Blood Cell Formation Blood cell formation occurs within marrow cavities Skeletal Classification There are 206 bones in the human skeleton Grouped according to: The Axial Skeleton (80 bones) Forms the long axis (trunk) of the body Function: Protecting, Supporting, Carrying body parts Skull, Vertebral Column, Rib Cage The Appendicular Skeleton (126 bones) Forms the appendages of the body Function: Locomotion, environmental manipulation Upper and Lower Limbs, Shoulders, Hips Also classified according to size and shape  Skeletal Classification Overview Blue = Axial Skeleton Yellow = Appendicular Skeleton Bone Classification Long Bones Consists of an elongated long shaft and two ends e.g: Finger bones, Femur Short Bones Generally cube-shaped, and stubby e.g: Wrist, Ankles, Patella (Sesamoid) Flat Bones Thin, flattened, and slightly curved e.g: Skull, Ribs, Sternum, Shoulder blades Irregular Bones Complicated shapes not fitting any classes e.g: Vertebrae, Pelvis Bone Classification Overview Skeletal Cartilage Water component lends resiliency Resists outward expansion Hyaline cartilage (Collagen) Support, flexibility, and resilience Ribs and joint surfaces Elastic cartilage (Elastin) External ear and epiglottis Fibrocartilage (Thick Collagen) Great tensile strength Menisci of knee; vertebral discs Skeletal Cartilage Overview Bone Structure Bone Macrostructure Most long bones consist of: Diaphysis (Shaft or Long Axis) Thick external collar of compact bone Central medullary cavity of bone marrow Epiphyses (Ends) Expanded end of the long bone shaft Consists mainly of spongy bone Periosteum (Membranes) Dual-layer covers entire external bone surface Supplied with nerve, lymphatic, and blood vessels Bone Macrostructure Overview Bone Microstructure Bones consist of two layers: Compact Bone (Hard) Osteon (Haversian System) - Mineralised, structural unit Haversian Canal - Contains capillary and nerve supply Volkmann’s Canal - Link blood and nerves to periosteum Spongy Bone (Cancellous) Trabeculae - Align along stress lines Lamellae - Deposited by osteocytes in rings Canaliculi - Canals joining lamellae and osteocytes Endosteum - Surrounds trabeculae providing nutrition Bone Microstructure Overview Bone Composition Bone has a solid matrix composed of: Osteoid - Organic; Collagen; Flexibility Mineral Salts - Inorganic; Ca3(PO4)2; Durability Matrix is maintained by specific cells: Osteocytes - Mature bone cells; Former osteoblasts Osteoblasts - Bone ‘forming’ cells; Add matrix Osteoclasts - Bone ‘degrading’ cells; Remove matrix Controlled and regulated by: Parathyroid Hormone (PTH) Blood Ca2+ levels ↓; Bone matrix degraded; Ca2+ released Calcitonin Blood Ca2+ levels ↑; Ca2+ deposited in bones; Ca2+ absorbed Bone Composition Overview Bone Regulation Overview  Edith Cowan University School of Science Skeletal System Growth and Repair Appositional Bone Growth Increase in bone thickness (width) Allows lengthening bone to widen Occurs throughout life Osteoblast role Secrete matrix on external bone under periosteum Osteoclast role Remove bone on endosteal surface Usually more secretion than removal Thicker, stronger bone without excess weight Appositional Growth Overview Interstitial Bone Growth Requires presence of epiphyseal cartilage Epiphyseal plate maintains constant thickness Cartilage growth on one side Balanced by bone replacement on other Chondrocytes rapidly divide Pushes epiphysis away from diaphysis (lengthening) Chondrocytes die and cartilage calcifies Replaced by spongy bone Epiphyseal plate thins and is replaced by bone Interstitial Growth Overview Bone Fractures Position of bone ends after fracture Non-displaced – ends retain normal position Displaced – ends out of normal alignment Completeness of break Complete – broken all the way through Incomplete – not broken all the way through Whether skin is penetrated Open (compound) – skin is penetrated Closed (simple) – skin is not penetrated May be due to mechanical stress or trauma Mechanical Bone Stress Types of Fractures Bone Repair Four stages of bone repair and remodelling 1. Haematoma Formation Torn vessels, clotting, phagocytes clear debris 2. Fibrocartilaginous Callus Collagen secreted, broken ends joined, spongy bone 3. Bony Callus Trabeculae appear in callus, compact bone forms 4. Bone Remodelling Excess materials removed, shaft walls reconstructed Stages of Bone Repair  Joints and Articulations Joint Classification Joints are classified functionally: Syntharthroses - Immovable joints Amphiarthroses - Slightly moveable joints Diarthroses - Freely moveable joints Joints are classified structurally: Fibrous - Immoveable or slightly moveable e.g: Skull sutures; Periodontal ligaments Cartilaginous - Immoveable and immobile e.g: Rib and sternum joints; Intervertebral discs Synovial - Highly moveable with fluid e.g: Majority of joints; Patella; Shoulder Joint Classification Overview Cartilaginous Joint Fibrous Joint Synovial Joint Synovial Joint Features Articular (Hyaline) Cartilage Prevents crushing of bone ends Joint (Synovial) Cavity Small, fluid filled space Articular (Joint) Capsule External fibrous layer – dense irregular CT Inner synovial membrane – makes synovial fluid Synovial Fluid Viscous; lubricates and nourishes cartilage Reinforcing Ligaments Stabilise the joint and associated structures Nerves and Blood Vessels Pain, position, stretch, filtrate for synovial fluid Synovial Joint Overview Synovial Joint Classifications  Edith Cowan University School of Science Skeletal System Tutorial (Answers) Questions Using the diagrams as a guide, identify the macro- and micro-structures of bone Questions Questions List the non-living components of bone → Non-living components → Collagen fibres, proteoglycans, glycoproteins, ground substance and minerals such as calcium and phosphate List the living components of bone → Cellular components → Osteocytes, osteoblasts, osteoclasts Questions What part of bone tissue is inorganic? → Matrix composed of calcium salts What part of bone tissue is organic? → Osteoid composed of collagen and ground substance Questions What is the function of the periosteum? → Protects bone and allows blood vessels and nerves to enter bone tissue → Also an attachment site for tendons and ligaments What membrane lines the internal canals and covers the trabeculae of spongy bone? → Endosteum Questions What is the function of the canaliculi? → Passageways for the movement of materials Distinguish between the epiphyseal disc and epiphyseal line → The epiphyseal disc is hyaline cartilage and the site of linear growth. When the cartilage is replaced by bone, a line of fusion remains Questions Using the diagram as a guide, outline the role of PTH in bone homeostasis Questions Questions Using the diagram as a guide, explain how healing of a bone fracture occurs Questions Questions What is ostealgia? → Pain in a bone What do you think a long bone would look like at the end of adolescence if remodelling did not occur? → Its shaft would still be its original length and it would have two very elongated and expanded ends Questions Why is adequate dietary calcium necessary for the development of strong bones? → Bone is formed of calcium salts; insufficient calcium weakens bones What characteristics do all joints have in common? → Consist of bony regions held together by cartilaginous tissue or joint capsules Questions What is osteoporosis? → Bone density regulated by sex hormones → ↓ oestrogen = ↑ osteoclast activity → Bone matrix is degraded, bone density ↓ → Increased risk of fractures (porous bones) What is rickets? → Poorly mineralised bones occurring in children → Causes bow legs and bone deformities → Decreased calcium or Vitamin D in diet → Vitamin D promoted intestinal calcium absorption Questions Using the diagram as a guide, identify the structures of a synovial joint Questions Questions Describe the structure of the synovial joint → Synovial joints are freely moveable joints → They have two articulating surfaces covered in hyaline cartilage → Surrounded by a fluid-filled joint capsule → Comprised of fibrous connective tissue → Joint capsule is lined with a synovial membrane Questions Outline the structure and function of articular cartilage → Articular cartilage is made up of chondrocytes, water, and a collagen and glycoprotein matrix → Its function is to reduce friction between the articulating bones, and to distribute the pressure generated by weight bearing Questions What is osteoarthritis? → Decrease in articular cartilage caused by use → Bone ends become exposed and erode → Inflammation and restricted movement result What is rheumatoid arthritis? → Inflammation of the synovial membrane → Inflammatory factors destroy local tissues → Scarring occurs which then ossifies → Bone ends fuse immobilising the joint Questions Why are there more tendinous muscle attachments to bone than direct attachments? → They conserve space (less bulky), are durable, and can span bony prominences Relate the degree of movement to each of the three main types of joint → Immovable joints are called synarthroses (fibrous) → Partially moveable joints are called amphiarthroses (gel) → Freely moveable joints are called diarthroses (fluid) Questions Why would it be anatomically ‘silly’ to have the sturdiest vertebrae in the cervical region instead of the lumbar region of the spine? → The lumbar region bears the greatest weight so its vertebrae are the sturdiest What is chiropractic? → A system of treating disease by manipulating the vertebral column based on the theory that most disease are caused due to pressure on nerves or faulty bone alignment Questions Based on shape, classify the following bones: → Flat → Short → Long → Sesamoid → Irregular Questions Identify each of the following synovial joints: → Saddle → Hinge → Plane → Condyloid → Ball-and-socket → Pivot  Edith Cowan University School of Science Musculoskeletal System Muscle Structure Muscle Characteristics Over 600 muscles perform four functions: Movement - Internally and externally Posture - Continually adjust against gravity Stabilises - Pulls on bones to stabilise joints Heat - Generates heat with contraction Muscle characteristics include: Excitability - Receive and respond to a stimulus Contractility - Ability to contract or shorten Extensibility - Ability to stretch to original length Elasticity - Ability to resume tension after stretching Fibre Arrangement Classified according to fibre arrangement Parallel (Fusiform) Long, parallel, strap-like; Cover long distances Convergent Fan-shaped; Converge at insertion Pennate (Pinnate) Short; Many fibres per unit area Circular Circular fibre bands; Surround body openings Fibre Arrangement Overview Muscle Interactions Attachments to bone: (In at least two places) Origin - Immovable bone; Lies close to Insertion Insertion - Movable bone; Moves towards Origin Interactions with other muscles: Prime mover - Provides major force for movement Synergist - Adds force to action of prime mover Antagonist - Opposes movement, usually relaxed Fixator - Immobilises bones and/or origins Muscles can only pull, never push Attachments and Interactions Antagonist Fixator Primer mover Primer mover Synergist Antagonist Muscle-Bone Interactions Levers - Rigid bar that moves on a fixed point Fulcrum - Fixed point around which the lever moves (Joint) Effort - Applied force used to move a resistance Load - Resistance which is moved by force Three types of bone-muscle levers: First Class Lever Effort and Load opposite; Fulcrum in between Second Class Lever Effort and Fulcrum opposite; Load in between Third Class Lever Load and Fulcrum opposite; Effort in between Lever Systems  Muscle Structure Supporting Structures Composed of connective tissue Wrap, bind and protect muscles cells Epimysium Outer layer surrounding whole muscle Perimysium Middle layer surrounding muscle fibre bundles Endomysium Inner layer surrounding each muscle fibre Continuous with tendons Attach muscles to bones → bone is moved Supporting Structures Overview Muscle Macrostructure Connective tissue coverings Fascicles are formed by bundled muscle fibres Fascicles are composed of myofibrils Muscle fibres (often called cells) Myofibrils multinucleate contractile cells Composed of myofilaments (molecular structure) Defined by sarcomeres (contractile units) Nerve Supply Muscle fibres supplied with motor units for contractibility Blood Supply Waste removal, ATP delivery, O2 delivery Fascicles and Myofibrils Myofilaments and Sarcomeres Myofilament Structure Molecular structure if muscles Thick filaments Two polypeptide chains, two globular heads This forms a myosin molecule Heads contain ATP binding sites Thick filaments contain 200 myosin molecules Thin filaments Globular proteins linked into chains These form actin molecule Strengthened by tropomyosin protein strands Contains myosin bindings sites (troponin) Myofilament Overview Sarcomere Muscle structure in cross and sagittal section Myofibrils are banded or striated (sarcomeres) Due to molecular arrangement of proteins Sarcomere regions: A Band: Thick filaments H Zone: Thick and thin filaments do not overlap M Line: Holds adjacent thick filaments together I Band: Thin filaments Z Disc: Thin filaments joining sarcomeres Titin provides strength and recoil Sarcomere Overview Skeletal Muscle Structure Overview  Edith Cowan University School of Science Musculoskeletal System Muscle Contraction The Neuromuscular Junction Motor neuron binds to muscle tissue Separated by synaptic cleft Impulse arrives Ca2+ enters axonal end Ca2+ causes vesicle production (ACh) Vesicles release ACh into synaptic cleft ACh travels across synaptic cleft ACh binds to receptors on junctional folds Causes release of Ca2+ from SR Neuromuscular Junction - Macro Neuromuscular Junction - Micro Sarcoplasmic Reticulum Network surrounding each myofilament Houses Ca2+ for muscle contraction (2nd messenger) Ca2+ released on muscle stimulation Penetrates each muscle fibre Transfers stimulus into muscle depths Terminal cisternae Longitudinal cross channels T-tubules Elongated tubes entering cell depths The Sarcoplasmic Reticulum Neuromuscular-SR Interface Role of Ionic Calcium Actin filaments contain binding sites Binding sites composed of: Troponin and Tropomyosin (Troponin Complex) When Ca2+ levels are low Tropomyosin ‘blocks’ actin binding sites When Ca2+ levels increase They bind to Troponin causing shape change Tropomyosin moves away from site Binding sites free for myosin Role of Ionic Calcium Overview Sliding Filament Model Thick Filaments: globular heads Thin Filaments: binding sites Ca2+ ‘unlocks’ Actin binding sites causing: 1. Cross-Bridge Attachment Actin and Myosin bind 2. ‘Power’ Stroke Myosin pivots and pulls on Actin filament 3. Cross-Bridge Detachment Actin and Myosin detach 4. ‘Cocking’ of Myosin Myosin head resumes initial position Filaments overlap causing contraction Sliding Filament Model Overview Muscle Comparisons  Edith Cowan University School of Science Muscular System Tutorial (Answers) Questions Using the diagram as a guide, identify the components of lever systems Questions Questions Using the diagram as a guide, identify the structures of skeletal muscle Questions Questions Consider the term epimysium. What is the meaning of epi? → Outer What is meaning of mys? → Muscle How do these word stems relate to the role and position of this connective tissue sheath? → The epimysium covers the external surface of the muscle Questions List three reasons why connective tissue wrappings of skeletal muscle are important → Bundle muscle fibres together → Add strength to muscle → Provide route for blood vessels to fibres Questions Using the diagram as a guide, identify the structures associated with sarcomeres Questions Questions Which of the following structures would contain the highest concentration of Ca2+ in a muscle cell? (T tubule, mitochondrion, SR) → The SR which is a calcium storage depot What is a strain? → A ‘pulled muscle’ caused by excessive stretching of a muscle due to overuse or abuse (becomes inflamed and local joints become immobilised) Questions Explain what is happening in each stage Questions Questions What is the function of pre-synaptic Ca2+? → To initiate the production of neurotransmitter- containing vesicles What is the function of cholinesterase? → To degrade acetylcholine in the synapse What is the advantage of having cholinesterase at the neuromuscular junction? → To prevent multiple impulse transmission Questions Questions Why is Ca2+ called the final trigger for contraction? → Calcium binding to Troponin frees the active sites on Actin to bind with Myosin cross bridges What constitutes the initial trigger? → Neurotransmitter binding (generates action potential along sarcolemma) Questions Using the diagram as a guide, identify each stage of muscle contraction and explain what is happening Questions Questions What would be the result if the muscle fibre suddenly ran out of ATP when the sarcomeres had only partially contracted? → The sarcomeres would remain in their partially contracted state What is a sarcolemma? → The plasma membrane surface of a muscle fibre Questions Which energy-producing pathway would predominate in the leg muscle of a long distance cyclist? → Aerobic pathway What causes muscle cells to undergo gradual muscle fatigue? → An ATP deficit creates lactic acid thus an ionic imbalance occurs contributing to muscle fatigue Questions What is a spasm? → Sudden involuntary muscle twitch → Can be irritating or painful → Caused by chemical imbalances → Psychological factors (eyelids or face = Tics) → Stretching or massaging may help What is a cramp? → A prolonged spasm → Usually occurs at night or after exercise Questions What will happen to a muscle in the body when its nerve supply is destroyed or badly damaged? → It becomes flaccid, paralysed, and atrophies. Nerve stimulation is necessary for viable muscles What is PRICE? → Acronym for Prevention, Rest, Ice, Compression, Elevation - the standard treatment for pulled muscles Questions What is tetanus? → An acute infectious disease caused by Clostridium tetani and resulting in persistent painful spasms of some skeletal muscles → Begins gradually with stiffness of jaw and neck muscles and progresses to fixed rigidity of the jaws (lockjaw) and spasms of trunk and limb muscles → Usually fatal due to respiratory failure or exhaustion  Edith Cowan University School of Science Fundamentals of Nervous Tissue Nervous Tissue Structures, Functions and Divisions The ‘control centre’ of the human body General functions: Gathers sensory information Processes and interprets sensory input Effects a response Comprised of two main systems: Central Nervous System Peripheral Nervous System Divided into eight functional divisions Structures and Functions Functional Divisions Nervous Tissue Provides ability to react to stimuli Unique tissue characteristics: Extreme longevity (100+ years) Amitotic High metabolic rate Two principal cell types in nervous tissue: Neurons Receive conduct, transmit impulses Neuroglia Support, protect, connect neurons Neuron Structure Myelination Neuroglia Schwann Cells Form myelin sheath around PNS neurons Oligodendrocytes Form myelin sheath around CNS neurons Microglial Cells Migratory phagocytes of the CNS Astrocytes Form blood-brain barrier in the brain Ependymal Cells Circulate CSF in brain ventricles and spinal column Satellite Cells Packing cells between PNS cell bodies Neuroglia Overview Neuron Classification Three main types of neurons: Sensory (Detection) Afferent Dorsal fibres Unipolar Association (Connection) Connecting Interneurons Bipolar Motor (Movement) Efferent Ventral fibres Multipolar Essential for reflex arc function Can be myelinated or unmyelinated Neuron Classification Overview  Edith Cowan University School of Science Nervous System Peripheral and Autonomic Nervous Systems Peripheral Nervous System PNS contains multiple divisions Provides innervation throughout the body Nerves Nerve endings Sensory receptors Sensory Receptors Able to respond to stimuli Changes in the environment Internal or external Send information to PNS then to CNS Sensation: awareness of the stimulus Perception: interpretation of stimulus meaning Sensory receptors are classified by: Type Location Structure Sensory Receptors - Stimulus Type Mechanoreceptors Respond to mechanical stress of cells (e.g: Skin) Thermoreceptors Respond to temperature change (e.g: Hot and Cold) Photoreceptors Respond to changes in light (e.g: Rods and Cones) Chemoreceptors Respond to chemical in solution (e.g: Taste buds) Nociceptors Respond to damaging stimuli (e.g: Pain) Sensory Receptors - Location Exteroceptors Respond to external stimuli Near or at body surface e.g: touch, pressure, pain Interoceptors Sometimes called visceroceptors Respond to internal stimuli Arise from internal viscera and blood vessels e.g: baroreceptors, chemoreceptors, Proprioceptors Respond to internal stimuli Arise from muscles, ligaments, joints Respond to sense of position e.g: body movement, alignment, orientation Sensory Receptors Location - Overview Exteroceptor Mechanoreceptor (Pain, Temp, Chems) (Light Pressure) Proprioceptor (Muscle/Tendon Stretch) Mechanoreceptor (Deep Pressure) Sensory Receptors - Non-Encapsulated Sensory Receptors - Encapsulated Nerve Structure Nerves are collections of neurons outside CNS Also containing blood vessels Enclosed in connective tissue: Endoneurium (In) - Delicate (Single Neurons) Perineurium (Mid) - Course (Single Fascicles) Epineurium (Out) - Fibrous (Entire Bundle) Pass through vertebral spaces (Foramina) All nerves are mixed nerves Contain sensory and motor roots Nerve Structure Overview Cranial Nerves Twelve pairs associated with the brain I. Olfactory Associated with smell (olfaction) II. Optic Sensory nerve of vision III. Oculomotor Supplies four of the six eye muscles IV. Trochlear Pulley muscle of the eye V. Trigeminal Supplies sensory fibres to the face and jaw Cranial Nerves VI. Abducens Turns eyeball laterally VII. Facial Muscles of facial expression VIII. Vestibulocochlear Sensory nerve for hearing and balance IX. Glossopharyngeal Innervates the tongue and pharynx X. Vagus Extends into the thorax and abdomen XI. Accessory Moves the head and neck XII. Hypoglossal Innervates the tongue mucles Cranial Nerves Overview Spinal Nerve Arrangement Pass through vertebral spaces (Foramina) All spinal nerves are mixed nerves Sensory (Afferent/Dorsal) Roots Motor (Efferent/Ventral) Roots There are 31 pairs of spinal nerves: Cervical (C1-C8): 8 nerve pairs Thoracic (T1-T12): 12 nerve pairs Give rise Lumbar (L1-L5): 5 nerve pairs to Sacral (S1-S5): 5 nerve pairs plexuses Coccygeal (C0): 1 nerve pair Spinal Nerve Arrangement Overview Plexuses and Dermatomes Spinal nerves innervate surrounding tissues Function is affected downwards from nerve Four main plexuses: Cervical (C1-C4): Head, neck, shoulders Brachial (C5-T1): Chest, shoulders, arms Lumbar (T12-L4): Back, abdomen, groin, legs Sacral (L4-S4): Pelvis, buttocks, genitals, legs Thoracic nerves serve internal organs Intercostal nerves (T1-T12) Dermatomes serve skin regions (Diagnostic) Thoracic Nerves Plexuses and Dermatomes Overview Reflex Arcs Rapid, predictable, motor response to stimuli Reflex arcs contain five components: 1. Receptor: Site of stimulus action 2. Sensory Neuron: Afferent pathway toward CNS 3. Integrator: Synaptic interchange within CNS 4. Motor Neuron: Efferent pathway away from CNS 5. Effector: Muscle or gland response Two basic reflex arc types: Stretch Reflex Afferent-Efferent neuron interaction e.g: Knee Jerk Withdrawal Reflex Requires interneuron e.g: Hand Burning Reflex Arc Overview Reflex Types Overview Stretch Reflex Withdrawal Reflex (No Brain Input) (Brain Input) Autonomic Nervous System Controls all non-conscious actions e.g: thirst, hunger, voiding, Divided into two divisions: Sympathetic: emergency situations ‘Fight or flight’ (positive feedback) Parasympathetic: energy conserving ‘Rest and digest’ (negative feedback) PSNS and SNS Innervation PSNS and SNS Effects ANS Receptors Cholinergic receptors Bind acetylcholine Two types: Nicotinic - always stimulatory Muscarinic - can be stimulatory or inhibitory Adrenergic receptors Bind adrenaline and noradrenaline Two types: alpha (α) beta (β) Functions can be stimulatory or inhibitory ANS Neurotransmitters  Edith Cowan University School of Science Nervous System Tutorial Questions Using the diagram as a guide, identify the structures and functional lobes Questions What type of sensory information is relayed to sensory areas of the cerebellum? What structures return CSF to the bloodstream? A brain haemorrhage on the right side of the brain results in paralysis of the left side of the body. Why? Questions What is the function of the pons? What is the function of the medulla oblongata? Where are these structures located? What is the function of the reticular formation? Questions Using the diagram as a guide, identify the structures associated with the meninges Questions How are the brain and spinal cord protected against compression and damage? What is in the central canal of the spinal cord? How does the arrangement of grey and white matter in the brain and spinal cord differ? Questions Why are spinal nerves mixed nerves? Define a nerve plexus The spinal cord is enlarged in which two regions? What is the significance of these enlargements? Questions Using the diagram as a guide, identify the spinal cord structures and associated functions Questions Where in the vertebral column is a lumbar puncture done? Why is this the site of choice? Questions What information would you get from performing a lumbar tap? Which spaces of the spinal cord are filled with CSF? Questions Using the diagram as a guide, identify the structures within a peripheral nerve Questions What is paraesthesia? What is neuralgia? What is an analgesic? Questions What symptoms might be expected if the following cranial nerves were damaged? Optic nerve Vestibulocochlear Glossopharyngeal nerve Hypoglossal nerve Questions Using the diagram as a guide, identify the components of a reflex arc Questions Why are cell bodies of sensory neurons located to one side of the impulse pathway? What is sensory adaptation? Questions Provide an example of a slow adapting receptor Provide an example of a fast adapting receptor What is the difference between sensation and perception? Questions In which areas of the body is the density of sensory receptors: The greatest? The lowest? Relate this to the density of receptor fields Questions What kind of sensory receptor is involved? You are standing in the hot sun You step on a sharp nail Someone taps you on the shoulder You eat a piece of fruit and it tastes strange You trip on uneven pavement and start to fall You walk out of a dark room into the sunlight  Edith Cowan University School of Science Endocrine System Glands and Hormones Hypothalamus Responsible for ANS functions Temperature, hunger, thirst, fatigue Not considered an endocrine gland But has some endocrine functions Releases hypothalmic hormones Via hypophyseal-portal system These stimulate/inhibit pituitary hormone secretion Homeostatic functions: Blood Pressure, Heart Rate, Temperature, etc Hypothalamus Overview Pituitary Gland Composed of two lobes: Posterior Lobe Does not produce hormones Stores and releases hypothalamic hormones Communication via hypothalamic neurons Anterior Lobe Produces its own hormones Releases its own via hypothalamic signals Communication via hypophyseal capillaries Posterior lobe attached via the Infundibilum Pituitary Hormones Pituitary Hormones – Cont. Anterior Pituitary Posterior Pituitary Pituitary Overview Pineal Gland Small, cone-shaped gland Located on the roof of the third ventricle Deep within the brain opposite hypothalamus Functions are still largely unknown Produces: Melatonin Part of diurnal cycle ↑ melatonin = drowsiness ↓ melatonin = alertness Pineal Gland Overview Thyroid Gland Located on the trachea Bi-lobed organ either side of trachea Consists of follicles Produces: Calcitonin - Calcium metabolism Thyroid Hormone (TH) - Glucose oxidation Triiodothyronine (T3) - Temperature, growth, HR Thyroxine (T4) - Metabolic processes Thyroid Gland Overview Parathyroid Glands Located behind the thyroid gland Number in adults varies from 4 to 8 Found in the neck but also throughout thorax Posterior surface of the thyroid gland Tissues densely packed with cells Produces: Parathyroid Hormone (PTH) Releases calcium in the blood when levels fall Affects bones, kidneys, intestines in the process Parathyroid Glands Overview PTH Function Thymus Gland Located deep within the sternum Diminishes in size with age Becomes fatty and fibrous Composed of two identical lobes Specialised organ of the immune system Produces: Thymopoietin - T-cell marker in immune system Thymosin - Stimulates production of T-cells Thymus Gland Overview Adrenal Glands “Ad” - near; “Renal” - Kidneys Composed of cortex and medulla tissue Each produces different hormones Produces: Corticosteroids (Cortex - Steroid-based) Aldosterone - Na+ control via kidneys Cortisol - Immune response Androgens - Gonad development Catecholamines (Medulla - AA-based) Adrenaline - ‘Fight or Flight’ response Adrenal Glands Overview Pancreas Located partially behind the stomach Contains endocrine and exocrine tissue Hormonal and digestive functions Islets of Langerhans contain endocrine tissue Produces: Insulin Lowers blood sugar levels Converts glucose to fat Glucagon Converts glycogen to glucose When blood levels lower Pancreatic Function Gonads Maintain function of reproductive system Oval-shaped glands (analogous structures) Ovaries (Female); Testes (Male) Produce: Oestrogen Secondary female sex characteristics Progesterone Maintain menstrual cycle Testosterone Secondary male sex characteristics Sperm production  Gonads Overview Ureter Fallopian Tube Seminal Vesicle Follicular Tissue Prostate Uterus Ductus Deferens Ovary Cervix Penile Broad Shaft Ligament Vagina Testis Spongy Urethra Nervous Vs Endocrine Function  Edith Cowan University School of Science Endocrine System Mechanisms of Action The Endocrine System Glands that produce chemical messengers Hormones are secreted into the bloodstream They control: Reproduction, Growth, Development Homeostasis, Metabolism Hormonal stimuli produce the following events: Alters plasma membrane permeability Stimulates protein synthesis Activates or deactivates enzymes Induces secretory activity Stimulates mitosis The Endocrine Glands Hormones Hormones are liquids Crystalline structure Chemical messengers for communication Elicit specific responses from target organs Effect rate is specific - Quick or Slow acting Hormones are: Steroids (Cholesterol) Proteins (Amino Acids) Hormones can be produced and/or stored Control of Release Hormones can be Excitatory or Inhibitory Release is controlled by stimuli that are: Humoral - Osmotic and solute concentrations Neural - Hypothalamus and Pituitary Hormonal - Stimulating and Inhibiting hormones Release occurs in three ways: Direct - Immediate release Delayed - Stored hormone release Indirect - Messengers trigger hormone release Control of Release Overview Hormone Action Mechanisms of Action Steroid and protein hormones function differently Based on polarity of hormone Specific receptors are needed for function Effects vary as hormones bind to receptors: Membrane permeability can be altered Cyclic AMP can be activated Genes in the nucleus can be activated Receptors can be found: Plasma membrane (On) - Proteins Sub-membrane (In) - (Steroids and Proteins) Hormone Action Steroid Hormones (Non-polar) Diffuse directly through plasma membrane Bind to receptors in the cytoplasm Receptor-Chaperonin complex binds to DNA Induces transcription of target genes Amino Acid Hormones (Polar) Membrane receptors relay message (ATP required) Message relayed to sub-membrane receptors Activates cAMP in cytoplasm (2nd messenger) cAMP triggers responses in target cell Hormone Action Overview Steroid and Non-Steroid Hormones  Edith Cowan University School of Science Endocrine System Tutorial Questions Describe the anatomical relationship between the hypothalamus and the pituitary gland Questions How do cells in the hypothalamus control the secretion of the cells of the anterior pituitary? Where are the hormones of the posterior pituitary produced and how do they get to the posterior pituitary? What is meant by an antagonist? Questions Why is the nervous system like ‘SMS’ while the endocrine system is like ‘Email’ in terms of speed? What is a target organ? Questions If hormones travel in the bloodstream, explain why not all tissues respond Compare the location of receptors for protein- based and steroid-based hormones. Questions A Is this an example of a B 1 protein-based or steroid- based hormone? C E D 2 F G Identify structures (A-J) 3 Identify processes (1-5) H 4 I 5 J Questions Is this an example of a protein-based or steroid- based hormone? Identify items (A-E) A B D E C Questions How do first messengers differ from second messengers? Questions Explain insulin and glucagon antagonism using the diagram as a guide Questions Explain PTH and calcitonin antagonism using the diagram as a guide Questions Explain the thyroxine feedback loop Questions Which hormones produced in inadequate amounts result in the following? Excessive urination Loss of glucose in the urine Abnormally small stature Mental and physical sluggishness Questions Which hormones produced in excessive amounts result in the following? Large hands and feet Nervousness and sweating Spontaneous fractures Reduction of pain and swelling  Edith Cowan University School of Science SCN1111 Human Processes 1 Final Exam Revision Final Exam This must be completed in two parts: Multiple Choice (15%) To be completed online Link provided in Canvas During Week 13 Short Answer (35%) To be completed on-campus During University Exam weeks Timetabled centrally (see SIMO) See Canvas: Assignments > Final Exam Unit Outcomes Overview ‘Unit Introduction’ in Canvas Learning Objectives Within each Module in Canvas At the top of each page Use this as a checklist for learning/study For example: Modules Examined Students should base their study on all 'ECU branded' materials provided in Canvas (Lectures and Tutorials), as well as information provided during tutorials (note-taking during class is essential). All content in these Modules is examinable. Students will also need to consider that the following course learning objective will feature in the exam: Outcome 1: Apply broad health knowledge to a range of theoretical and practical nursing situations. Module 7 (Blood) Module 8 (Skeletal System) Module 9 (Muscular System) Module 10 (Fundamentals of the Nervous System) Module 11 (CNS, PNS, and ANS) Module 12 (Endocrine System) Study Resources To address Learning Objectives See ‘Textbook’ in Canvas Review quiz materials in Canvas (Modules 7-12) View YouTube Videos and Additional Resources Final Tips Eat well and rest well See ‘Exam Tip’ sheets Find a study method that works for you Read the questions carefully! Write responses in your own words Assessing understanding not English Answer all questions Do not leave anything blank Utilise the entire time (time management)  SAMPLE Sample Only Unit Code and SCN1111 Human Processes 1 Title Student Number SURNAME/FAMILY NAME OTHER OR GIVEN NAME/S Please print clearly NOTE: THIS PAPER IS INTENDED AS A SAMPLE OR GUIDE ONLY. THIS IS NOT INDICATIVE OF THE QUESTIONS THAT WILL BE IN THE FINAL EXAM. PART A: MULTIPLE CHOICE QUESTIONS 1. Which one of the following statements correctly describes activities of muscles? a. All muscles are attached to bones b. All muscles shorten when they contract c. All muscles are under conscious control d. All muscles are synergistic 2. Contraction of a skeletal muscle cell is initiated by the: a. release of sodium ions by the neuron into the neuromuscular junction b. release of acetylcholine by a neuron terminating at the neuromuscular junction c. hormones delivered by the blood supply to the nearby tissue d. release of calcium ions by the neuron into the neuromuscular junction 3. All of the following are necessary for contraction to occur EXCEPT which one? a. ATP must be present b. Cross-bridges must form between actin and myosin c. Troponin-tropomyosin complex must shift out of the way d. The troponin and tropomysin must slide relative to each other, shortening the sarcomere 4. Once a muscle cell has depleted its small supply of ready-made ATP, what will it use next for energy? a. Phospholipids b. Glycogen c. Creatine phosphate d. Proteins 5. The primary energy source used by muscle cells to generate ATP is: a. steroids b. glucose c. fatty acids d. glycogen 6. When an electrical impulse traveling along a motor neuron arrives at a neuromuscular junction: a. a new electrical impulse is generated that returns the message to the original nerve b. calcium is transported back to the sarcoplasmic reticulum c. there is an increase in the secretion of acetylcholine at the neuromuscular junction d. sliding of actin and myosin filaments is inhibited 7. All of the following are functions of bone EXCEPT which one? a. serving as an endocrine organ, secreting several different hormones b. red blood cell formation c. mineral storage d. attachment of muscles, enabling movement 8. Which one of the following statements CORRECTLY describes the location of compact bone and spongy bone? a. Compact bone covers the ends of the bone and forms the shaft, and spongy bone is inside the ends, under the compact bone b. Spongy bone is found throughout the shaft and ends, covered by a thin layer of compact bone c. The ends of long bones are solid compact bone, and the shaft is predominantly spongy bone d. Spongy bone is found on the outside of the shaft, and compact bone forms the hard core of the shaft 1 9. A typical long bone has an epiphysis at each end, which can be thought of as: a. yellow bone marrow b. an enlarged knob c. a site of water storage d. a tough layer of connective tissue 10. Bones continue to lengthen throughout childhood and adolescence because: a. the activity of osteoblasts cannot be reduced until adulthood b. a growth plate is present in each epiphysis until the late teens c. ossification cannot occur until after puberty d. the production of cartilage for a lengthening bone occurs primarily on the inside of the growth plate 11. Which one of the following statements is TRUE regarding parathyroid hormone (PTH)? a. It is released when blood calcium levels are high b. It causes decreased activity of osteoclasts c. It has the same function as calcitonin d. It causes the breakdown of bone 12. Osteoporosis is a common condition that essentially results when homeostasis cannot be maintained in ________ and ________. a. chondroblasts, osteoclasts b. canaculi, osteoclasts c. osteoclasts, osteoblasts d. canaculi, chondroblasts 13. A clear fluid lubricates: a. synovial joints b. ligaments c. fibrous joints d. hyaline cartilage 14. In which one of the following locations would one find a cartilaginous joint? a. between the scapula and humerus b. between the lower ribs and sternum c. in a ball-and-socket joint d. between the frontal and parietal bones 15. Which one of the following statements is TRUE regarding fibrous joints? a. Fibrous joints present at birth between bones of the skull develop into sutures in the adult b. The bones are separated by a fluid-filled cavity that lubricates the joint c. They include hinge joints and ball-and-socket joints d. They are freely movable and can bend and rotate 16. Straps of connective tissue that hold bones together, support joints, and direct movement are known as ________. a. cartilages b. tendons c. ligaments d. bursae 2 17. Which of the following is INCORRECT about the human skeleton? a. It can store fat b. It can produce blood cells c. It is composed only of a solid non-living matrix d. It can release phosphorous 18. Which of the following cells form new bone in bone tissue? a. Osteons b. Fibroblasts c. Osteocytes d. Osteoblasts 19. About 55% of whole blood is ________, which is/are mostly made up of water. a. clotting proteins b. haemoglobin c. white blood cells d. plasma 20. When the hormone erythropoietin is released in response to low oxygen levels, where is it transported to stimulate red blood cell production? a. Kidney b. Spleen c. Liver d. Red bone marrow 21. Which one of the following population of cells is most markedly increased during bacterial infections? a. Platelets b. Neutrophils c. Lymphocytes d. Monocytes 22. Unlike white blood cells, red blood cells lose their ________ and ________ as they mature. a. nucleus, organelles b. nucleus, ATP c. nucleolus, cytoplasm d. flexibility, shape 23. When a blood vessel gets damaged, contractions of smooth muscle referred to as ________ help constrict the vessel to reduce blood flow. a. vascular spasms b. haemostasis c. formed elements d. endocytosis 24. Eosinophils are especially important in defending the human body from infection by: a. moulds b. viruses c. large parasites d. bacteria 25. Hormones act upon specific target tissues because: a. they can be released only following depolarization of the target cell b. the blood has access to all body tissues 3  c. they are released next to target tissues, so they cannot interact with other cells d. target tissues display the appropriate receptor for a particular hormone 26. All of the following statements about the endocrine system are TRUE EXCEPT which one? a. Hormones exert their effects on cells that have the specific hormone receptor b. Many hormones are not able to cross the blood-brain barrier c. Hormones act more quickly than the nervous system d. Hormones are distributed via the circulatory system 27. Which one of the following parts of the brain links to the endocrine system? a. Thyroid b. Hypothalamus c. Posterior pituitary d. Anterior pituitary 28. When oxytocin is released during childbirth, the hormone targets cells in the: a. Breasts b. Kidneys c. Uterus d. Both the breasts and uterus 29. Insulin helps regulate blood sugar at homeostatic levels by: a. activating hormone production in the posterior pituitary gland b. promoting the entry of glucose into cells c. stimulating the breakdown of glycogen to glucose d. stimulating alpha cells of the pancreas to produce more hormones 30. Which one of the following causes the release of adrenaline and noradrenaline from the adrenal medulla? a. ACTH from the anterior pituitary b. AMTH form the anterior pituitary c. Sympathetic nerves d. Releasing hormone from the hypothalamus 31. The central nervous system is composed of which of the following? a. Autonomic nervous system and brain b. Somatic division and motor division c. Brain and spinal cord d. Somatic division and autonomic division 32. Which one of the following provides the central nervous system with information about the outside environment? a. Parasympathetic division b. Autonomic division c. Motor division d. Sensory division 33. Electrical impulses are transmitted between components of the central nervous system via which one of the following? a. Glial cells b. Interneurons c. Motor neurons d. Sensory neurons 4 34. Which one of the following cells transmit impulses away from the central nervous system to the muscles and other organs? a. Neuroglia b. Dendrites c. Sensory neurons d. Motor neurons 35. Which one of the following establishes and maintains the resting potential? a. Sodium-potassium pump b. K+ leak channel c. Depolarization d. Repolarization 36. A neuron at rest has a charge difference across its cell membrane, with the interior of the cell negative relative to the exterior. This difference in charge across the plasma membrane is referred to as ________ potential. a. action b. refractory c. resting d. depolarization 37. All of the following are functions of the myelin sheath EXCEPT which one? a. The myelin sheath is involved in the repair of damaged neurons in the peripheral nervous system b. The myelin sheath insulates a neuron and saves the neuron energy c. The myelin sheath plays an important role in synaptic transmission d. The myelin sheath speeds up transmission of action potentials 38. Oligodendrocytes are similar to Schwann cells in that they: a. are located in the peripheral nervous system b. help neurons regenerate after injury c. are located in the central nervous system d. are a type of neuroglial cell 39. Cells that provide direct protection and physical support to neurons are: a. nodes of Ranvier b. found primarily in lymphatic fluids c. located only in the spinal fluid d. neuroglial cells 40. Saltatory conduction is: a. an action potential generated in taste receptors or buds b. the movement of an electrical impulse from the dendrite to an axon c. the movement of neurotransmitters across a synaptic cleft d. the process of conduction leaping along myelinated neurons 41. Which one of the following is NOT directly involved in the production of a typical spinal reflex? a. Interneuron b. Motor neuron c. Brain d. Sensory neuron 5 42. Control of smooth muscle and internal organs is the role of the ________ division of the nervous system? a. endocrine b. autonomic c. postsynaptic d. sensory 43. Both voluntary and involuntary skeletal muscle movement are controlled through which one of the following divisions of the nervous system? a. Sympathetic division b. Somatic division c. Endocrine division d. Sensory division 44. Which one of the following divisions of the nervous system predominates during the relaxed state? a. Parasympathetic division b. Somatic division c. Sympathetic division d. Sensory division 45. Which one of the following activities would be facilitated by the sympathetic nervous system? a. increased bladder contraction b. decreased heart rate c. increased blood pressure d. increased digestion and absorption 46. The central nervous system is enclosed by membranes or meninges called the: a. glial, Schwann, and interstitial b. dura mater, alma mater, and pia mater c. dura mater, pia mater, and arachnoid d. fore, mid, and hind meninges 47. During a brain surgery, a surgeon passes an instrument through the dura mater. Which one of the following does the surgeon pass through next? a. Bones of the skull b. Cerebrospinal fluid c. Pia mater d. Arachnoid 48. The region of brain that coordinates antagonistic muscle movements is the: a. occipital lobe b. cerebellum c. medulla oblongata d. pons 49. Control of respiratory rate, heart rate, and blood pressure is integrated through the: a. cerebellum b. cerebral cortex c. medulla oblongata d. hypothalamus 6 50. Regulation of the production of breast milk, carbohydrate metabolism, and temperature control are some of the functions of the: a. frontal lobe b. medulla oblongata c. thalamus d. hypothalamus 51. The left and right sides of the cerebrum are interconnected by which one of the following? a. Medulla oblongata b. Corpus callosum c. Cerebral cortex d. Pons 52. Excitatory neurotransmitters encourage the generation of new electrical impulses by which one of the following? a. Stimulating depolarization of postsynaptic neurons b. Stimulating saltatory conduction c. Inhibiting postsynaptic neurons from repolarizing d. Stimulating depolarization of presynaptic neurons 53. During synaptic transmission, the influx of ________ causes vesicles in the axon bulb to fuse with the cell membrane, releasing ________. a. Ca2+, neurotransmitter b. neurotransmitters, Ca2+ c. mitochondrion, neurons d. neurons, mitochondrion 54. Axons branch into axon terminals, which have ________ located at the terminal ends. a. hillocks b. bulbs c. dendrites d. Schwann cells 55. Olfactory receptors are located in which one of the following? a. Upper part of nasal passages b. Taste buds c. Upper regions of mouth d. Skin surrounding nasal openings 56. Different pitched (high or low) sounds are discriminated by the: a. hair cells in specific regions of the cochlea b. malleus, incus, and stapes c. tympanic membrane d. round and oval windows 57. Which one of the following structures is used to sense rotational movement of the head and body? a. Ampulla and cupula b. Stapes c. Oval window d. Semicircular canals 7 58. An individual never developed otoliths in the inner ear due to a genetic defect. Which one of the following will be impaired as a result? a. Hearing low-pitched sounds b. Sense of rotational movement c. Sense of head position d. Sense of direction of movement 59. The "blind spot" is associated with which one of the following? a. Vitreous humor b. Fovea centralis c. Optic disk d. Lens 60. Insufficient number of particular types of cones causes: a. impaired night vision b. impaired colour vision c. detachment of the retina d. macular degeneration END OF PART A 8 PART B: SHORT ANSWER QUESTIONS Answer these questions in the spaces provided on the paper. 1. The following diagram shows a transection of the human brain and meninges. 4 2 3 5 6 1 7 i. What is found in the structure at (3)? _______________________________________ (1 Mark) ii. How does the substance found in the structure at (3) assist nervous tissue? _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (2 Marks) iii. What is the function of the structure at (5)? _________________________________________________________________________ (2 Marks) iv. What is the function of the structure at (6)? _________________________________________________________________________ (2 Marks) v. Explain what would occur if the structure at (7) became damaged. _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (1 Mark) 9 2. A highly-strung teenager was suddenly startled by a loud bang that sounded like a gunshot. Her heartbeat accelerated rapidly. When she realised that the noise was only a car backfiring, she felt relieved but her heart kept beating heavily for several minutes more. i. Which division of her Autonomic Nervous System (ANS) was affected? _________________________________________________________________________ (1 Mark) ii. Which hormone was responsible for her accelerated heartbeat? _________________________________________________________________________ (1 Mark) iii. Identify and explain two ‘symptoms’ (other than accelerated heartbeat) that occur as a result of this hormone. _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (4 Marks) iv. Why does it take a long time to calm down after we are scared or nervous? _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (2 Marks) 3. Outline six differences between the diaphysis and the epiphysis of long bones. _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (6 Marks) 10 4. List the two main classes of leukocytes. Select one example of each and explain its distinguishing characteristics and function. _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (8 Marks) 5. Describe the anatomical relationship between the hypothalamus and the pituitary gland. _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ (10 Marks) END OF EXAMINATION PAPER 11