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Biology Std 10-Function and location Study notes Plant Physiology Organ Lenticels Cuticle Mesophyll Cells Location On the surface of old, woody stems Wax like covering on epidermis of leaves & green stems Between the epidermal cells of the leaf. Cambium Below the bark of the tree Xylem Veins of leaf, stem and leaves/ Innermost part of Vascular bundles Found in the veins of leaf, stem and leaves /Periphery of the Vascular Bundles Special openings on the leaf margin Between the epidermal cells of the leaf/ On either side of stoma. In the cytoplasm of green plant cells In the chloroplast Colourless ground substance present in the chloroplast Minute openings(surrounded by guard cells) occurring in large number on the lower surface of leaf Phloem Hydathodes Guard Cells Chloroplast Thylakoids/ Grana Stroma Stoma 1 Function Exchange of photosynthetic and respiratory gases Prevent Transpiration Traps light energy with the chloroplast present in them for photosynthesis Increases the girth of the stem Conducts water from the roots to the aerial parts of plant. Translocates the prepared food in the leaves to the storage organs. Guttation Regulate the opening and closing of the stoma Photosynthesis Site of Light Reaction Site of light independent reaction Diffusion of photosynthetic and respiratory gases , Transpiration Circulatory System Structure 1) Heart 2) Pericardial fluid 3) Sino atrial node (S A node) or Pacemaker. 4) Atrio Ventricular node. (AV node) 5) Bundle of His 6) Bicuspid valve or mitral valve. 7) Tricuspid valve. 8) Chordae tendinae. 9) Pulmonary semilunar valve. 10) Aortic semilunar valve. 11) Coronary artery Location Situated between the two lungs in the thoracic cavity. The apex is tilted towards the left side. Found in the pericardial cavity, between the two membranes of pericardium. Function Pumps oxygenated blood to the different parts of the body. Protects the heart from mechanical injury and shock. Acts as a lubricant and reduces friction for the beating of the heart. Keeps the tissues of the heart moist. Upper wall of right atrium. Initiates the heart beat. Regulates the contraction of the auricles. Bottom of the right auricle. Regulates the contraction of the ventricles. Arises from the A V node and It receives an impulse from the A V consists of a left and right node and transmits it to the Purkinje branch which extends upto fibres. the apex of the heart. Between the left auricle and Allows the blood to flow from the left ventricle of the heart. auricle to the left ventricle and prevents it from going back into the auricle. Between the right auricle and Allows the blood to flow from the ventricle of the heart. right auricle to the right ventricle and prevents it from going back into the auricle. Extend from the papillary Keeps the tricuspid and bicuspid muscles to the pointed ends valves in position and prevents them of the cuspid valves. from upturning. At the opening of the Prevents backflow of deoxygenated pulmonary artery which blood into the right ventricle. arises from the right ventricle. At the opening of the aorta Prevents backflow of oxygenated which arises from the left blood into the left ventricle. ventricle. Arises from the aortic arch, Supply oxygenated blood to the walls near its base as it emerges of the heart. from the heart. 2 Excretory System Structure 1) Kidney 6) Proximal convulated tubule Location Lie along the posterior abdominal wall one on either side of the vertebral column. They arise from the renal pelvis of the kidneys at the hilum and the other end opens into the urinary bladder. Sac like structure situated in the lower end of the abdomen into which the other end of the ureter opens. Short, muscular tube arising from the neck of the urinary bladder and leading to the outside. Knot of capillaries present in the cup of the Bowmans capsule. Lies in the cortex of the kidney. 7) Loop of Henle Present in the renal medulla. 8) Distal convulated tubule. 9) Collecting duct Present in the cortex of the kidney. Formed by the union of collecting tubules passes through the cortex , medulla and opens into the pelvis of the kidney. 2) Ureters 3) Urinary bladder 4) Urethra 5) Glomerulus Function Excretion . Osmoregulation. Transports urine from the pelvis of the kidney to the urinary bladder. Temporary storage of urine. Allows the passage of urine outside the body. Brings about ultrafiltration of urine. Reabsorbs most water and much of glucose and sodium and chloride ions. Absorption of water and sodium ions. Tubular secretion, Reabsorption of remaining chlorides and some water. Pours urine into the pelvis of the kidney. Endocrine System Structure 1) Adrenal gland Adrenal Cortex. Location Cap like structure above each kidney. Outer region of the adrenal gland. 3 Function Secretes corticoidsGlucocorticoids. mineralocorticoids. Sex corticoids. Adrenal medulla. Inner region of the adrenal gland. 2) Thyroid gland Situated on the lateral and ventral sides of the trachea, just below the larynx. 3) Pancreatic gland Below the stomach, at the loop of the duodenum. 4) Pituitary gland SL. NO Secretes adrenaline which prepares the body in an emergency situation for fight or flight response. Secretes thyroxine which regulates the basal metabolic rate of the body. Secretes hormones like Glucagon and insulin. Glucagon increases blood sugar level by converting glycogen into glucose. Insulin controls the blood sugar level by converting glucose into glycogen. Attached to the hypothalamus or Anterior lobe of pituitary secretes below the hypothalamus. hormones like growth hormone and tropic hormones such as TSH, ACTH, LH, FSH. Posterior lobe of pituitary secretes hormones like Oxytocin and Vassopressin.(ADH) THE NERVOUS SYSTEM Parts of a neuron LOCATION 2. NAME OF STUCTURE Perikaryon 1 / cyton / cell body Dendrites 3 Axon 4. Myelin sheath Covering /surrounding the axon .5. Nodes of Ranvier 6. 7. Neurilemma Terminal branches /axon terminals Unmyelinated gaps between the myelin sheath. Surrounding the myelin sheath Posterior end of the axon. 8. Synaptic bulb Proximal part of a neuron Cytoplasmic projections of cyton/ perikaryon Long process of the cell body Distal end of the terminal branches 4 FUNCTION Typical cellular structure. Centrosome absent. Receives nerve impulses and conducts it to the cyton. Conducts nerve impulses away from the cyton. Prevents the mixing of nerve impulses. Increases the speed of nerve impulse conduction. Increases the speed of nerve impulse conduction. Protects the axon. Receives nerve impulses conducted through the axon and transmits it to the next neuron. Contains chemicals called neurotransmitters (eg. acetylcholine).When the nerve impulse reaches the terminal 9. Neurotransmitters Found in the synaptic bulb. 10. Synapse Is the junction between the terminal branches of one neuron and the dendrites of the adjacent neuron. branches, neurotransmitters are released by the synaptic bulb, Neurotransmitters are released into the synapse by the synaptic bulb. Hence these chemicals are responsible for transmission of nerve impulses from the terminal branches of one neuron to the dendrites of the next neuron. Neurotransmitters are released in to the synapse, which sets off a wave of excitement in the next neuron. Types of neurons 1. Sensory neuron 2. Motor neuron 3 Association neuron Extends from receptors( sense organs) to Central Nervous System Extends from the Central Nervous System to the effectors (muscles and glands) Found in the spinal cord and brain Transmits nerve impulses of stimuli received from the sense organs to brain or spinal cord Transmits nerve impulses for response from CNS to the muscles and glands. Interconnect the sensory neuron and the motor neuron. THE BRAIN A. Protective layers of the brain 1. Meninges Outer protective layer of the brain 2. Cerebro spinal fluid (CSF) Found between the layers of the meninges. 5 Tough layer, hence protects the internal delicate parts of the brain. It contains blood vessels and so nourishes the brain Serves as a shock absorber Maintains constant pressure in and around the brain. Helps in exchange of nutrients and waste products between nerve tissue and blood. B. Parts of the brain 1. Cerebrum Forebrain Part of the fore brain and is the largest part of the brain. 2. Corpus callosum Transverse band of nerve fibres, internally joining the two cerebral hemispheres. 3. Diencephalon made up of the Hypothalamus and the Thalamus Between the two cerebral hemispheres, just superior to the mid brain. 1. Mid brain. Mid brain Between the anterior and posterior part of the brain Hind brain Located under the cerebrum 1. Cerebellum 2. Pons Between the two lobes of the cerebellum on the ventral side. 3. Medulla oblongata Below the cerebellum 6 It is the seat of intelligence, memory, thinking, reasoning and emotions Centre for perception of stimuli for vision, smell, taste and hearing. All voluntary activities are initiated in the cerebrum. Transmits nerve impulses from the right cerebral hemisphere to the left hemisphere and vice versa. Hypothalamus: Controls pituitary gland, sleeping and waking patterns, hunger and thirst. Also regulates body temperature. Thalamus: interprets sensory impulses such as pain, touch and pressure. It relays sensory impulses from the spinal cord to the thalamus. It relays motor impulses from the thalamus to the Spinal cord. Maintains the body balance. Coordinates the movements of the skeletal muscles. Transmits nerve impulses across the two lobes of the cerebellum, thus ensuring a coordination of muscular movements on both sides of the body. Controls the involuntary activities such as breathing and heart beat. Also controls peristaltic movements of the alimentary canal. 1. Tear glands EYE Under the upper eyelids, at the upper, outer corner of the orbit of the eye. Secretes tears- cleanses the eye by washing away foreign substances that may enter the eye. Contains lysozymes- this protects the eye from infections. Protects the surface of the eye. 2. Conjunctiva Covering of the entire front surface of the eye, continuous with the inner eyelids. 3. Sclera 4. Cornea Outermost white layer of the eyeball. Anterior, bulging and transparent part of sclera. Provides and maintains the shape of eyeball. Refracts the light rays as they pass through it. 5. Choroid Middle layer of the eye, inner to the sclera. As it is pigmented, it absorbs light rays and prevents total internal reflection of the light rays. Blood vessels present here, nourish the eye. 6. Iris Located between the lens and the cornea. It regulates the amount of light entering the eyeball, by increasing or decreasing the diameter of the pupil. It gives colour to the eye. 7. Pupil Opening seen in the center of the iris. It admits light rays into the eyeball. 8. Ciliary body Swollen portion of the choroid, Ciliary processes secrete at the junction of the choroid aqueous humour. and iris. Ciliary muscles alter the shape of the eye lens for accommodation. 9. Suspensory ligaments Extends from the ciliary muscles to the eye lens. Holds the eye lens in position. Along with ciliary muscles alter the shape of the eye lens for accommodation. 10.. Retina Innermost layer of the eyeball, adhering to the choroid and ending at the edge of the ciliary body. It is the photosensitive layer of the eye. Provides the screen for image formation. Rods Present at the periphery of the Respond to low light intensity 7 (contain a pigment called Rhodopsin) retina. and so enable vision in dim light. Cones (contain a pigment called Iodopsin) Present mainly at the yellow spot. Are specialized for colour vision and for vision in bright light. 11. Optic nerve Leaves the eye at the blind spot and reaches the occipital centre of the brain. Transmits nerve impulses from the sensory cells (rods and cones) of the retina to the visual area (occipital region) of the cerebrum for interpretation. 12. Lens Located behind the iris and pupil, supported by the suspensory ligaments. Refracts and focuses the light rays on the retina. Clear vision of both far and near objects is obtained due to its ability to change its focal length with the help of the ciliary muscles and suspensory ligaments. 13. Aqueous humour In the anterior chamber, between the lens and the cornea Keeps the cornea moist. Protects the lens from mechanical shocks Helps in refraction of light rays. 14. Vitreous humour In the vitreous chamber, between the lens and the retina. Maintains the shape of the eyeball. It refracts the light rays before it reaches the retina. It protects the retina. 15. Yellow spot On the retina, in line with the horizontal axis of the eyeball. It is the region of brightest and sharpest vision as it contains the highest concentration of cones. 16. Blind spot Opening lateral to the yellow spot, where the optic nerve leaves the eyeball. This is an area of no vision, since rods and cones are absent here. 1. 2. Ear pinna Auditory canal EAR External ear Either sides of the head. Extends from pinna to the tympanum. 8 Collects sound waves and directs it into the auditory canal. Directs sound waves to the ear drum / tympanum. 3. Tympanum / ear drum Stretched tightly between the external and middle ear. 1. Ear Ossicles 2. Eustachian tube 3. Oval window On the inner boundary of the middle ear and inner ear The sound vibrations from the stapes (middle ear) is transmitted through the oval window to the cochlea of the inner ear.(this in turn sets the fluid in the cochlea to vibrate) 4. Round window Below and a little behind the oval window. When the stapes transmits vibrations to the oval window, the round window moves outwards. This enables the fluid in the cochlea to move freely. Middle ear Made up of three small bones. a. Malleus is hammer shaped. Its handle rests on the tympanum and the head rests on the incus. b. Incus- is the central small bone and is anvil shaped. c. Stapes- is stirrup shaped and its base is attached to the oval window. Extends from the pharynx to the cavity of the middle ear. Inner ear (Membranous labyrinth) Bony canal made of two and half spirals in the inner ear. Found in the lower portion of the labyrinth. In the middle canal / median canal/cochlear canal of the cochlea. 1. Cochlea 2. Organ of Corti 3. Semi circular canals Set of three fluid filled canals arranged at right angles to each other. Found in the upper portion of the labyrinth. 4. Vestibule Forms the central portion of 9 When sound waves strike its surface, it vibrates. These sound vibrations are then transmitted to the middle ear. The 3 ossicles form a leverage system. They amplify the sound waves received from the external ear and transmit these sound vibrations to the internal ear. It equalizes the air pressure on either sides of the ear drum. Contains the Organ of Corti which is responsible for hearing. Contains receptor cells which transform sound vibrations into nerve impulses. (It has different areas suited to interpret sounds of different frequencies.) Contains sensory cells responsible for dynamic balance. Contains sensory cells 5. Auditory nerve the labyrinth. It is made up of two sacs called the Utriculus and the Sacculus Extends from the inner ear to the temporal lobe of the cerebrum. responsible for static balance. Transmits nerve impulses from the Organ of Corti to the cerebrum. Male Reproductive System Organ Location Function Testes Contained in the thin walled scrotum Produces sperms & Hormone Testosterone. Seminiferous Tubules Present in the lobules of the testes Spermatogenesis (Produces sperms) Interstitial Cells / Leydig Cells Present as packing tissue in the lobules of the testes, between the seminiferous tubules. Produces the male hormone Testosterone Epididymis Fitting like a cap on the upper pole of each+ testis. Stores the sperms till they mature & become motile Vas Deferens Connects the epididymis to the urethra Transports sperms from the epididymis to the urethra. Penis Lies in front of the scrotum Serves for passing out of both semen and urine. Seminal Vesicles Between posterior surface of urinary bladder & rectum. To produce a sugary secretion which provides energy to the sperms. Prostate Gland Surrounds the Urethra, at the base of the Urinary Bladder. To produce an alkaline secretion to neutralises the acidic vagina. Bulbo urethral Gland or Cowper s gland Located beneath the prostrate gland on either side of the urethra. Its secretion lubricates the end of the penis during coitus. 10 Female Reproductive System Organ Location Function Ovaries Upper pelvic cavity, one on each side of uterus Oogenesis, Ovulation & Secretion of Hormone Progesterone & Oestrogen. Oviduct / Fallopian Tube/ Uterine Tube Extends laterally on each side of the uterus Site of fertilization /Picks up & transports the released ovum into the uterus. Oviducal Funnel Mouth of oviduct, with finger like projections called fimbriae & just above the ovary. Receives the released ovum and pushes it into the oviduct. Uterus Pear shaped , hollow , muscular organ situated between urinary bladder and rectum. Protects & nourishes the developing embryo. Endometrium Innermost vascular layer of the uterus Thickens to receive the fertilized egg and gets discharged during the Menstrual Phase. Cervix A small lower constricted part of the uterus. Enlarges during parturition Vagina A muscular tube starting from lower end of the uterus to the outside Receives the penis during coitus (intercourse) Corpus Luteum Yellow remnants of the Graafian follicle after ovulation. Produces hormones after releasing the ovum. Amnion Surrounds the embryo except at the thick umbilical cord. Contains the foetus and the amniotic fluid. Amniotic Fluid A fluid within the amnion , surrounding the foetus Protects the embryo against mechanical jerks, Keeps even pressure around the embryo, Prevents sticking of the foetus to the amnion. Chorion Second layer of the foetal Supports the amnion 11 membranes. Allantois Forms the Villi of the placenta from the foetal side. Helps in diffusion of substances from the mother to the foetus & foetus to mother . Placenta A disc like structure attached to the uterine wall Diffusion of substances from the mother to the foetus & foetus to mother /Also acts as an endocrine gland Umbilical Cord A cord containing blood vessels connecting the placenta to the foetus. The only blood vascular connection between foetus and uterine wall. Hence transports substances from mother to foetus and vice versa. *************************************************************** 12
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