Please enable JavaScript.

Coggle requires JavaScript to display documents.

Bio - Coggle Diagram

- - - - Sexual Reproduction
        
        Two Parents, Gamete Fusion, Features from both Parents, More Common in Higher Plants
        
        in Flowers via Fertilization
        
        Flowers
        
        Whorls
        
        Corolla
        
        Petals
        
        1 more item...
        
        Androecium
        
        Male Reproductive Part
        
        Stamens
        
        2 more items...
        
        Gynoecium
        
        Female Reproductive Part
        
        Pistils/ Carpels
        
        4 more items...
        
        Calyx
        
        Sepals
        
        1 more item...
        
        Types Based on Whorls Present
        
        Complete or Bisexual/ Hermaphrodite Flowers
        
        Contain All Four Whorls
        
        eg. Pea, Rose
        
        Incomplete or Unisexual Flowers
        
        Staminate
        
        1 more item...
        
        Pistillate
        
        1 more item...
        
        Types Based on Pollination Agents Used
        
        Wind-Pollinated Flowers
        
        Unscented, Has Dully Coloured Petals, Stamens Outside Flower, Light, Small, Smooth Pollen Grains
        
        Insect-Pollinated Flowers
        
        Scented, Has Brightly Coloured Petals, Stamens Inside Flower, Large, Heavy, Spiky or Sticky Pollen Grains
        
        Pollination
        
        Transfer of Pollen Grains from the Anther to the Stigma of a Flower for Fertilization Execution
        
        Pollination Agents
        
        eg. Wind, Insects
        
        Types
        
        Self-Pollination
        
        Pollen Grains are Transferred from the Anther to the Stigma of the Same Flower or a Different Flower on the Same Plant
        
        Cross-Pollination
        
        Pollen Grains are Transferred from the Anther to the Stigma of the Different Flower of a Different Plant of the Same Species
        
        Double Fertilization
        
        Double Fertilization Process
        
        Pollen Grains Land on the Stigma to Germinate Pollen Tubes, Long Tubes that Grow through the Style and Reach the Ovary, Entering the Ovule, from which One Male Gamete Fuses with the Egg Cell to Form the Zygote, which then then Forms Embryo, and Another Fuses with the Secondary Nucleus to Form the Endospermic Nucleus, which then Forms the Endosperm
        
        Double Gamete Fusion
        
        Fruit
        
        Ripened Ovary, Contains One or More Seeds, Protects Seed from Insects, Diseases and Harsh Climatic Conditions
        
        Seed
        
        Ripened Ovule, Protected by a Seed Coat, the Ripened Ovule Walls, Contains the Embryo and in Endospermic Seeds, the Endosperm
        
        Embryo
        
        a Small, Living Plant which Becomes Active and Germinates under Suitable Conditions, Formed from the Endospermic Nucleus
        
        Parts
        
        Embryonal Axis
        
        2 more items...
        
        Cotyledons
        
        Germination
        
        Process of the Dormant Embryo Becoming Active and Beginning to Grow
        
        Conditions Required
        
        3 more items...
        
        Process
        
        1 more item...
        
        Types
        
        2 more items...
        
        Endosperm
        
        Special Food Storage Tissue
        
        Types Based on Endosperm Presence
        
        Endospermic Seeds
        
        Contains Endosperm
        
        eg. Rice, Wheat
        
        Non-Endospermic Seeds
        
        Does not Contain Endosperm
        
        eg. Pea, Bean
        
        Types Based on Cotyledon Number
        
        Dicotyledonous Seeds
        
        Contains Two Cotyledons, Food Stored in Cotyledons
        
        eg. Pea, Bean
        
        Monocotyledonous Seeds
        
        Contains One Cotyledon, Food Stored in Endosperm
        
        eg. Rice, Wheat
        
        Seed Dispersal
        
        via Wind
        
        Seeds are Light and Small with Wings or Feather-Like Apparatus
        
        via Water
        
        Seeds Can Float
        
        via Insect and Animals
        
        Seeds Have Sticky Surfaces or Hooks to Stick to Animal's Bodies to be Carried Off
        
        via Exploding Pods
        
        When Ripe, Seed Pods Burst
      - Asexual Reproduction
        
        Methods
        
        Budding
        
        a Nucleus, which is Divided from a Nucleus, Migrates to the Bud, a Small Outgrowth Develops on the Body of the Parent, and the Bud Detaches and Grows Independently
        
        eg. Yeast
        
        Fragmentation
        
        the Organism Breaks Up into Two or More Pieces, Called Fragments, which Each Grow Independently
        
        eg. Spirogyra
        
        Spore Formation
        
        Spore Sacs, Round, Oval Structures, Develop on the Body of the Parent, in which its Cytoplasm Divides Many Times into Spores, Tiny, Spherical, Unicellular Bodies, which have Thick Walls to Survive Harsh Conditions, and are Released when the Spore Sacs Open to be Carried by the Wind to Germinate in Favourable Conditions
        
        eg. Moulds
        
        Vegetative Propagation
        
        Plant Development from a Vegetative Part (ie. Roots, Stems, Leaves) without Seeds, Takes Less Time to Grow themselves and their Fruits
        
        Types Based on Parts Used for Propagation
        
        via Stem
        
        Corm
        
        1 more item...
        
        Tuber
        
        1 more item...
        
        Rhizome
        
        1 more item...
        
        Bulb
        
        1 more item...
        
        Runner
        
        1 more item...
        
        via Roots
        
        eg. Sweet Potato, Dahlia
        
        via Leaves
        
        eg. Bryophyllum, Begonia
        
        Artificial Propagation
        
        Vegetative Propagation Carried Out by Human Beings
        
        Types
        
        Stem Cutting
        
        2 more items...
        
        Layering
        
        2 more items...
        
        Grafting
        
        2 more items...
        
        Tissue Culture
        
        2 more items...
        
        Single Parent, No Gamete Fusion, Features from only Parent
- - - - Parts
        
        Blood
        
        Bright Red-Coloured Fluid that Circulates in the Entire Body to Transport Nutrients, Gases, Hormones, Enzymes and Waste Products, Regulates Body Temperature, Protects from Diseases, Prevents its Own Loss and Heals Wounds
        
        Parts
        
        Plasma
        
        Light Yellow Liquid Part of the Blood, is 90% Percent Water, Organic Components such as Glucose, Proteins, Amino Acids, Fats, Urea and Hormones and Inorganic Components such as Sodium Chloride and Sodium Bicarbonate
        
        Blood Cells/ Corpuscles
        
        Red Blood Cells (RBCs)/ Erythrocytes
        
        Small, 7 Micron Diameter, Biconcave, Minute, Disc-Shaped Cells, 5-6 Million Per Cubic mm of Blood, a Man Has More than a Woman, Does not Have a Nucleus if Mature, Produced in Bone Marrow, Lives for 120 Days, Contains Haemoglobin, Carries Oxygen and Carbon Dioxide to and from Cells
        
        Components
        
        3 more items...
        
        White Blood Cells (WBCs)/ Leukocytes
        
        Larger, Colourless, Indefinitely-Shaped Cells, 4000 to 8000 per Cubic mm of Blood, Has a Nucleus, Lives for 12 Hours to 12 Days, Protect the Body from Infection
        
        Types Based on Morphology
        
        2 more items...
        
        Types Based on Function
        
        2 more items...
        
        Blood Platelets/ Thrombocytes
        
        Minute, Colourless, Smaller Megakaryocyte Cytoplasm Cell Fragments, Does not Have a Nucleus, 200,000 to 400,000 per Cubic mm of Blood, Lives for 3-7 days, Helps in Blood Clotting by Collecting at the Wound Site to Block the Blood Flow
        
        Blood Transfusion
        
        Blood Transfer from a Donor to a Recipient, in which the Two Bloods Should Match, if Unsatisfied Blood Cells Clump Together, Blocking Blood Vessels, Causing Serious Consequences or Death, Caused by the Reaction between the Antigens of the Donor's Blood and the Antibodies of the Recipient's Blood
        
        Types Based on A and/ or B Antigen Presence
        
        Group A
        
        Has Antigen A, Can Donate to A and AB, Can Receive from A and O
        
        Group B
        
        Has Antigen B, Can Donate to B and AB, Can Receive from B and O
        
        Group AB
        
        Has Antigen AB, Can Donate to AB, Can Receive from A, B and O
        
        Group O
        
        Has no Antigens, Can Donate to A, B and AB, Can Receive from O
        
        Types Based on Rh-Factor Presence
        
        Rh-Positive
        
        85% of People, Can Donate to Rh+, Can Receive from Rh+ and Rh-
        
        Rh-Negative
        
        15% of People, Can Donate to Rh+, Can Receive from Rh-
        
        Blood Pressure
        
        Pressure Exerted by Circulating Blood on the Inner Walls of the Arteries
        
        Limits
        
        Systolic Pressure/ Upper Limit
        
        Pressure Produced in Ventricles When they Contract and Pump Blood into the Aorta and Pulmonary Artery, Equivalent to the Pressure Exerted by a 120mm Thick Mercury Column
        
        Diastolic Pressure/ Lower Limit
        
        Pressure Produced in the Ventricles when they Get Filled with Blood From the Atria, Equivalent to the Pressure Exerted by a 80mm Thick Mercury Column
        
        Diseases
        
        High Blood Pressure/ Hypertension
        
        Above 130/90 mm of Mercury
        
        Low Blood Pressure/ Hypotension
        
        Below Normal Pressure
        
        Normal Blood Pressure
        
        120/80 mm of Mercury
        
        Instrument: Sphygmomanometer
        
        Circulation
        
        Double Circulation
        
        Circulation between the Lungs, Heart and Body
        
        Process
        
        From the Superior and Inferior Vena Cava, to the Right Atrium, to the Right Ventricle, to the Pulmonary Artery to the Lungs for Oxygenation, to the Pulmonary Vein, to the Left Atrium, to the Left Ventricle, to the Aorta, to the Body Parts for Deoxygenation and Back to the Superior and Inferior Vena Cava
        
        Systemic Circulation
        
        Circulation between the Heart and the Body
        
        Pulmonary Circulation
        
        Circulation between the Lungs and the Heart
        
        Blood Vessels
        
        Types
        
        Arteries
        
        Deep-Seated, Red and Thick, Elastic Walled Blood Vessels that Generally Carry Oxygenated Blood from the Heart to the Body at High Speed and Under High Pressure, Valves are Absent
        
        Aorta
        
        Carries Oxygenated Blood from the Left Ventricle of the Heart to the Body
        
        Pulmonary Artery
        
        Carries Deoxygenated Blood from the Right Ventricle of the Heart to the Lungs
        
        Pulse
        
        the Regular Rhythmic Contraction and Relaxation of the Arteries
        
        Pulse Rate
        
        1 more item...
        
        Veins
        
        Superficial, Blue and Thin Walled Blood Vessels that Generally Carry Deoxygenated Blood to the Heart from the Body at Low Speed and Under Low Pressure, Valves are Present
        
        Superior Vena Cava
        
        Carries Deoxygenated Blood to the Right Atrium of the Heart from the Anterior Part of the Body
        
        Inferior Vena Cava
        
        Carries Deoxygenated Blood to the Right Atrium of the Heart from the Posterior Part of the Body
        
        Pulmonary Vein
        
        Carries Deoxygenated Blood from the Lungs to the Left Atrium of the Heart
        
        Capillaries
        
        Finest, One-Celled Thick Walled Blood Vessels which Connect Arteries with Veins, Oxygen and Nutrients from the Blood Diffuse through this to Reach the Cells, Form the Veins
        
        Tubular Structures through which Blood Circulates in the Body
        
        Heart
        
        Pumps Blood through the Body, Located in the Chest, Behind the Breastbone, Between the Lungs, Slightly Tilted to the Left, Weighs 300 Grams
        
        Pericardium
        
        a Double-Walled Protective Sac that Encloses the Heart, Consists of the Pericardial Fluid, Protects the Heart and Lubricates its Movement
        
        Chambers
        
        Auricles/ Atria
        
        Have Thin Walls, Receives Blood, Gives Blood to Ventricles, Contraction Creates a "Lub" Sound
        
        Left Auricle
        
        Carries Blood from the Pulmonary Vein to the Right Ventricle
        
        Right Auricle
        
        Carries Blood from the Superior and Inferior Vena Cava to the Right Ventricle
        
        Ventricles
        
        Have Thick Walls, Give Blood, Contraction Creates a "Dub" Sound
        
        Right Ventricle
        
        Carries Blood from the Right Auricle to the Pulmonary Artery
        
        Left Ventricle
        
        Carries Blood from the Left Auricle to the Aorta
        
        Sides
        
        Left
        
        Receives and Gives Oxygenated Blood, Contains the Bicuspid Valve which Allows the Blood Flow
        
        Right
        
        Receives and Gives Deoxygenated Blood, Contains the Tricuspid Valve which Prevents the Blood Backflow
        
        Heartbeat
        
        the Regular Rhythmic Contraction and Relaxation of the Heart, Occurs 80-100 per Minute
        
        Instrument: Stethoscope
        
        Systole
        
        Heart Contraction
        
        Diastole
        
        Heart Relaxation
    - - Consists of Lymph Vessels and Lymph Nodes
      - Components
        
        Lymph Vessels
        
        Minute Channels in which Lymph is Collected or Returned to a Vein
        
        Lymph Nodes
        
        Small Globular Masses Drained into from Lymph Vessels and Out Lymph Vessels Arise
        
        Lymph
        
        Slightly Yellowish Tissue Fluid Made up of Plasma and Leukocytes Filtered out from Blood, Composed of Less Proteins and More Lymphocytes, Help Fight Infections and Diseases
  - - - Mineral Absorption via Active Transport
        
        As the Mineral Concentration in the Root Hairs is Higher than in the Soil, the Minerals are Absorbed from the Soil into the Root Hairs with the Energy Expenditure
      - Water Absorption via Osmosis
        
        As the Water Concentration in the Soil is Higher than in the Root Hairs, the Water Flows inside the Root Hairs through the Cell Membrane
      - Water Absorption via Transpiration
        
        As the Water is Lost from Transpiration, a Suction Force, Called a Transpirational Pull, is Created to Pull Water From the Root Xylem and Reduce Water in the Roots for More Osmosis
      - Water Conduction
        
        As the Cortical Cells Become Turgid from the Accumulated Water in the Root Cortex, the Water is Pushed into the Xylem Vessels in the Upward Direction
      - Sap Ascension via Transpiration
        
        Sap Upward Movement that Contains Water and Minerals from the Root Xylem to the Stem and Leaves
      - Food Translocation
        
        Food Prepared in the Leaves is Translocated to Different Parts by the Phloem, a Sieve Tube System Placed One Above the Other to Form Long Tubes Upwards and Downwards
- - - - Brought about by the Brain, Nerves and Sense Organs
      - Nervous System
        
        Nerve Cells/ Neurons
        
        Transmit Messages from One Part of the Body to Another, Structural and Functional Unit of the Nervous System, Form Nerves, Many Long Fibres, Called Dendrons, Extend from Cell Body, which Further Divide to Form Dendrites, these include a Single Long Fibre, Called the Axon, which is Covered by the Myelin Sheath
        
        Message Transmission
        
        the Message, Called an Impulse, is Transmitted through a Gap, Called a Synapse, from the Axon Terminal of One Neuron to the Dendrites of Another Neuron which Reach its Axon Terminal to Have the Impulse Be Transmitted to the Dendrites of Another Neuron, a Muscle or a Gland
        
        Types
        
        Sensory Neurons
        
        Carry Impulses from the Sense Organs to the Spinal Cord or Brain
        
        Motor Neurons
        
        Carry Impulses from the Spinal Cord or Brain to the Muscles and Glands
        
        Association Neurons
        
        Carry Impulses from One Neuron to Another
        
        Organs
        
        Central Nervous System
        
        Brain
        
        Main Control Centre of Nervous System, Located in the Cranium/ Skull, Three Meninges, Membranes, Envelop the Brain, Have Cerebrospinal Fluid Between them to Nourish and the Brain and Protect it by Absorbing Shock
        
        Cerebrum
        
        Convoluted with Ridges and Grooves on the Surface to Increase Surface Area to Accommodates More Neurons, Divided Longitudinally by a Deep Furrow into the Left and Right Hemispheres, Consists of Grey Matter, the Outer Region Made of Greyish Neurons, and White Matter, the Inner Region Made of Whitish Neurons, it is Involved in the Functions of Intelligence, Consciousness, Memory, Will Power, Motor Functions and Sensory Processing
        
        Cerebellum
        
        Has Furrows and Grooves, Has Grey and White Matter, Coordinates Muscular Activities and Maintains Balance in Body
        
        Brainstem
        
        Connects the Cerebrum with the Spinal Cord, Consists of the Midbrain, Medulla Oblongata and Pons, Motor and Sensory Neurons Travel through the Brainstem to Allow for the Exchange of Signals between the Brain and Spinal Cord, Helps in Cardiovascular Control, Respiratory Control, Alertness, Awareness, Pain Sensitivity and Consciousness
        
        Consists of the Brain and Spinal Cord
        
        Spinal Cord
        
        Extension of the Medulla Oblongata, Long Cord-like Structure at the Back, Centrally Located and Well Protected by the Vertebral Column, Enveloped by the Same Three Meninges as the Brain and Contain Cerebrospinal Fluid Between them, the Grey Matter is on the Inside and the White Matter Lies on the Outside, Is the Central for Reflex Actions
        
        Peripheral Nervous System
        
        Connect the Central Nervous System to Other Parts of the Body, Consists of Nerves Arising from the Brain and Spinal Cord
        
        Cranial Nerves
        
        Emerge from the Brain and Keep it Informed about the Head Region, Twelve Pairs of these Nerves
        
        Spinal Nerves
        
        Emerge from the Spinal Cord and Reach Various Organs of the Body, Thirty One Pairs of these Nerves
        
        Autonomic Nervous System
        
        Consists of a Pair of Chains of Ganglia, Groups of Neuron Cell Bodies and Nerves Found on Either Side of the Backbone, Regulates Involuntary Actions of Internal Organs
        
        Sympathetic
        
        Prepares the Body to Face Emergency Situations
        
        Parasympathetic
        
        Re-Establishes Normal Conditions Once the Emergency is Over
    - - Brought about by the Hormones Secreted by Endocrine Glands
      - Hormones
        
        Chemicals which Help to Control and Coordinate Various Activities in the Body, Secreted by the Endocrine Glands
        
        Endocrine Gland
        
        Thyroid Gland
        
        a Bilobed Structure Present in the Throat Region that Produces Thyroxine
        
        Thyroxine
        
        Controls the Rate of Cellular Metabolism (ie. Cellular Oxidation), Iodine is an Important Constituent
        
        Hyperthyroidism
        
        Excessive Secretion of Thyroxine, Causes a High of Metabolism
        
        Hypothyroidism
        
        Decrease in the Secretion of Thyroxine, Causes a Sleepiness, Sluggishness, Increase in Weight, and Goitre, the Swelling of the Thyroid Gland
        
        Parathyroid Gland
        
        Four Small Glands Attached to the Thyroid Gland that Secrete Parathyroid Glands
        
        Parathyroid Glands/ Parathormone
        
        Controls the Amount of Calcium and Phosphorus in the Body
        
        Hyperparathyroidism
        
        Over-secretion Leads to Extra Deposition of Calcium in the Bones, Making them Thick and Brittle
        
        Hypoparathyroidism
        
        Deficiency Leads to the Depletion of Calcium and Phosphorus in the Teeth and Bones, Making them Soft
        
        Adrenal Gland
        
        Two, Each Located on Top of Each Kidney, Produces Adrenaline
        
        Adrenaline
        
        Prepares the Body to Meet Any Emergency Situation, Increases Heartbeat, Blood Pressure and the Supply of the Blood to the Muscles
        
        Pancreas
        
        Both a Endocrine and Exocrine Gland, Secretes Pancreatic Juice
        
        Pancreatic Juice
        
        Helps in Digestion in the Duodenum through a Duct, Contains the Islet of Langerhans which Release Insulin and Glycogen
        
        Insulin
        
        Controls the Amount of Glucose in the Blood by Converting Extra into Glycogen, which is Stored in the Liver
        
        Hyperglycemia
        
        1 more item...
        
        Hypoglycemia
        
        1 more item...
        
        Glucagon
        
        Converts Glycogen Back into Glucose in the Liver to Increase the Level of Sugar in the Blood :
        
        Testes
        
        Produces Testosterone
        
        Testosterone
        
        Produce Sperm, Stimulates the Development of Secondary Sexual Male Characters
        
        Ovary
        
        Progesterone and Oestrogen
        
        Help in Ovulation, Preparation of the Uterus for Implantation, Development of the Foetus and the Development of the Secondary Sexual Characters in Females
        
        Produces Progesterone and Oestrogen
        
        Pituitary Gland
        
        a Small Projection which Hangs Down from the Base of the Brain, Controls other Endocrine Glands
        
        Hormones Secreted
        
        Growth Hormone
        
        Promotes the Overall Growth of the Body
        
        Thyroid-Stimulating Hormone
        
        Stimulates the Thyroid Gland to Produce Thyroxine
        
        Follicle-Stimulating Hormone
        
        Stimulates the Growth of Ovaries and Testes at Puberty and Helps them to Produce Gametes
        
        Oxytocin
        
        Causes the Contraction of Uterine Muscles at the Time of Child Birth and Helps in the Expulsion of Milk from the Breasts
        
        Ductless Glands that Release Hormones Directly into the Blood
  - - - An Environmental Change that Causes an Organism to React
      - Sense Organs
        
        Contains Sense Receptors to Receive Stimulus and then Be Carried to the Brain or Spinal which Interprets the Message and Transmits it for the Required Response
        
        Eye
        
        Layers
        
        Choroid
        
        Thin Layer Behind the Rim of the Cornea, Richly Supplied with Blood Vessels, Contains Dark Black Pigment which Prevent Light Rays from Reflecting and Scattering inside the Eye, Completely Encloses the Eye Except for the Pupil in Front
        
        Pupil
        
        A Circular Window in the Centre of the Choroid
        
        Iris
        
        Part of Choroid Around Pupil, Contains Radial and Circular Muscles which Upon Contraction Widen or Constrict the Pupil
        
        Retina
        
        Innermost Layer Sensitive to Light, Contains Rod Cells, which are Receptors of Vision in Dim Light, and Cone Cells, which are Receptors of Vision in Strong Light and for Coloured Vision, Image Formed Here,
        
        Sclera
        
        Cornea
        
        Transparent Front Part of the Cornea, Protectively Covered by a Conjunctiva
        
        Outermost, Tough Layer, Gives Shape and Protects the Delicate Inner Parts of the Eye, White and Thick Except for the Cornea in Front
        
        Used to See Objects, Located in Deep Sockets, Called the Eye Sockets on the Front Side of the Head, Can Be Rotated in the Socket with Muscles, Tear Glands/ Lacrimal Glands Produce Tears which Wash the Eyes, to Keep them Clean and Lubricate them, Each is in the Form of a Ball Known as an Eyeball, Have Movable Eyelids to Protect their Outer Surface
        
        Other Parts
        
        Lens
        
        A Clear, Flexible, Transparent Biconvex Lens, behind the Pupil and Iris, Held in Position by Suspensory Ligaments of the Ciliary Body, Divides the Inner Cavity of the Eyeball into Two Chambers
        
        Aqueous Cavity
        
        Front Chamber between the Lens and Cornea, Filled with Aqueous Humour
        
        Aqueous Humour
        
        Keeps Lens Moist and Protects it from Physical Shock
        
        Vitreous Cavity
        
        Larger Cavity of Eyeball Behind Lens, Filled with Vitreous Humour
        
        Vitreous Humour
        
        a Transparent Jelly-like Substance that Helps Maintain the Shape of the Eyeball and Protects the Retina
        
        Working
        
        Light Rays Strike an Object, Get Reflected and Fall on the Cornea, Passing through the Pupil and Lens, and the Muscles Attached to the Lens Control its Focal Length so that it Focuses Light from Near or Far Objects on to the Retina to Form an Image and the Rods and Cones Converts the Image into an Impulse and Sends it through the Optic Nerve, Made of Sensory Neurons, to the Brain which Interprets the Impulse and Enables Us to See an Object
        
        Ear
        
        Parts
        
        Middle Ear
        
        Contains Tiny Bones - the Ear Ossicles, which Consist of the Hammer (Malleus), Anvil (Incus) and Stirrup (Stapes), the Handle of the Hammer Bone is Attached to the Inner Surface of the Eardrum and the Anvil, which is Connected to the Stirrup
        
        Internal Ear
        
        In Two Parts - Cochlea and Semicircular Canals -the Cochlea is a Spiral-Shaped Tube of Two and a Half Turns Filled with a Fluid and Contains Hair-like Structures - Sensory Cells - which Hear Sounds and are Interpreted in the Hearing Centre of the Cerebrum; there are Three Semicircular Canals Arranged at Right Angles to Each Other, which Contains Fluids that Helps Maintain the Balance of the Body
        
        External Ear
        
        the Earlobe/ Pinna Collects Sound Waves which Travel Inwards to a Tympanic Membrane/ Eardrum through the Auditory Canal,
        
        Helps in Hearing and Maintaining the Balance of the Body
        
        Nose
        
        Olfactory Receptors - Receptors for Smell - are Present within a Small Patch in the Upper Portion of the Nasal Cavity which Sends Impulses to the Cerebrum through the Olfactory Nerves
        
        Tongue
        
        Senses Taste with Taste Buds, a Group of Sensory Cells that Have Nerve Fibres Extending from their Bases, which Forms the Taste Nerve that Carries Impulses to the Taste Area of the Brain
        
        Skin
        
        Dermis
        
        Inner, Thick, Strong and Flexible Layer Made up of Connective Tissue and Contains Blood Vessels, Nerve Fibres, Sensory Receptors, Hair Follicles, Sweat Glands and Oil Glands, Nerve Endings Relay Messages Between the Skin and the Brain, the Touch and Pressure Receptors are Concerned with the Sensation of Touch, Pain, Temperature and Pressure, Hair Follicles Enclose the Roots of Hair, Sweat Glands are Simple Coiled Tubes which Help to Keep the Body Cool by Giving off Moisture in the Form of Sweat, Oil/ Sebaceous Glands Secrete the Oil Sebum which Makes Hair and the Outer Surface of the Skin Oily and Waterproof to Prevent the Loss of Water Via Evaporation
        
        Epidermis
        
        Outer Layer of the Skin, Made of Epithelial Tissues, Devoid of Blood Vessels, Innermost Layer Contains a Brown Pigment Called Melanin, which Determines the Colour of the Skin and Protects the Inner Parts of the Body from the Harmful Effects of the Ultraviolet Rays of the Sun, Outermost Layer Consists of Dead Cells
        
        Sense Organ for Touch, Pain, Pressure and Temperature, Made of Two Layers
    - - The Reaction of an Organism to a Stimuli
      - Reflex Action
        
        Automatic Responses to Stimuli
        
        Stimuli to Reflex Transmission
        
        When a Stimulus is Detected, An Impulse is Generated and Carried through Sensory Neurons to the Spinal Cord by a Receptor of the Sense Organ and the Impulse is Passed on to Motor Neurons through Association Neurons, Causing the Effector Organ to React