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ENDOCRINE SYTEM, HUMAN SYSTEM, Human skeleton consists of 206 bones which…

- - - - Target Organ
    - - via blood
    - - chemical regulators
- - - - stimulates
        
        Anterior Pituitary Hormones
        
        secretes
        
        ACTH
        
        Controls
        
        Secretion of steroid hormones from cortex region of adrenal glands
        
        secretes
        
        Prolactin
        
        stimulates
        
        Lactation, growth of mamary glands
        
        plays role in
        
        Carbohydrate and fat metabolism
        
        secretes
        
        TSH
        
        controls
        
        Secretion of hormones from thyroid gland
        
        secretes
        
        MSH
        
        infuences
        
        Skin pigmentation in some vertebrates
        
        infuences
        
        Fat metabolism in mamals
        
        secretes
        
        FSH and LH
        
        stimulates
        
        Ovary
        
        2 more items...
        
        Testes
        
        2 more items...
        
        secretes
        
        STH
        
        promotes
        
        Fat metabolism rather than glucose metabolism
        
        stimulates
        
        Muscles, bones and cartilage grow
        
        During childhood
        
        Excess STH can cause gigantism
        
        Lack of STH can cause dwarfism
        
        During adulthood
        
        Excess STH can cause acromegaly
  - - - secretes
        
        Oxytocin
        
        stimulates
        
        Milk glands
        
        induces
        
        Uterine contractions
      - secretes
        
        ADH
        
        Enhances
        
        water reabsorption
        
        Balance
        
        Osmotic pressure
        
        Negative feedback
        
        Less water in blood ➝ hypothalamus ➝ ADH ➝ kidney ➝ reabsorbs water makes blood more dilute
- - - - stimulates
        
        Metabolism
      - influence
        
        Development and maturation
      - Increase
        
        Protein synthesis during growth
        
        blood pressure and heart beat rate and metabolic rate
        
        Aerobic respiration
      - feedback mechanism
        
        Hypatalamus ➝ secretes RH ➝ Anterior Pituitary ➝ secretes TSH ➝ Thyroid ➝ Thyroxine ➝ Hypotalamus
  - - - decreases
        
        Ca2+ level of blood
        
        reabsorbtion of Ca2+ in kidney
      - stimulates
        
        Ca2+ deposition in bones
      - Increase
        
        Excretion of Ca2+ by urine
      - to balance calcium
        
        Works antagonistically with parathyroid hormone
  - - - STIMULATES
        
        Thyroid Gland
        
        RELEASES
        
        Calcitonin
        
        Stimulates Ca2+ deposition in bones
        
        Reduces Ca2+ uptake in kidneys
        
        Decreases Ca2+ uptake in intestines
        
        Homeostasis Normal blood calcium level
    - - STIMULATES
        
        Parathyroid Glands
        
        RELEASES
        
        PTH
        
        Increases Ca2+ uptake in intestines
        
        Increases Ca2+ uptake in kidneys
        
        Stimulates Ca2+ release from bones
- - - - stimulates
        
        Bones to release calcium into the blood when calcium levels are low.
      - cause
        
        kidneys to reduce calcium secretion into urine
      - Tetani
        
        Excess PTH
        
        Calcium level in the blood increases, bones get weak.
- - - - Cortisol
        
        controls
        
        The body’s use of fats, proteins and carbohydrates
        
        stimulates
        
        Production of glucose from fats and aminoacisd and reduce inflammation
        
        regulates
        
        Blood pressure
        
        High level of cortisol cause
        
        Cushing syndrome:Can cause health problems such as; unhealthy cholesterol levels, blood clots in the legs and lungs, high blood pressure
    - - Aldosterone
        
        regulates
        
        Salt and water balance in blood
        
        stimulates
        
        Reabsorbtion of sodium and water into the blood
        
        excrete
        
        potassium
        
        Low levels of aldosterone cause
        
        Addison disease: Characterized by low blood pressure, bronzing of skin and open infections
    - - Androgenes
        
        The adrenal cortex also produces small amount os steroid sex hormones; estrogen, progesterone and testosterone.
    - - Effects of Aldosterone
        
        1)Retention of sodium ions and water by kidneys ➝ 2)Increase blood volume and blood pressure
      - Effects of Cortisol
        
        1) Proteins and fats broken down and converted to glucose, leading to increased blood glucose ➝ 2)Possible suppression of immune system
    - - Corticostroids in response to stress
  - - - Noradrenaline
      - Adrenaline(Epinephrine)
        
        BOTH
        
        Trigger the release of
        
        Glucose and fatty acids into blood
        
        Increase
        
        oxygen delivery to body cells
        
        During a stressful situation, it's quickly released into the blood
- - - - secretes
        
        Testosterone
        
        Is a male hormone
        
        responsible for
        
        Development and maintenance of the male reproductive system
        
        Development of male secondary sex characteristics
        
        promotes
        
        Sperm formation
  - - - Growth, development, reproductive cycle and sexual behaviors
  - - - Estrogen
        
        responsible for
        
        Development of female secondary sex characteristics
        
        maintenance of the female reproductive system
        
        stimulate (at puberty)
        
        maturation of ovaries and other sexual organs
    - - STH and LH
    - - Prosterone
        
        involved in
        
        Preparing and maintaining the uterus
- - - - decrease
        
        blood glucose level
      - works antagonistically with glucagon to adjust glucose level
        
        Blood glucose level rises
        
        STIMULATES
        
        Beta cells of pancreas
        
        RELEASE
        
        Insulin
        
        2 more items...
        
        Blood glucose level falls
        
        STIMULATES
        
        Alpha cells of pancreas
        
        RELEASE
        
        Glucagon
        
        1 more item...
      - increases
        
        The permeability of cells to take glucose level
        
        Glucose metabolism in cells
      - Conversion of
        
        Glucose to glycogen as storage from in liver and muscles
      - Lack of insulin
        
        decrease number of beta cells
        
        Blood glucose level is above normal level
        
        can caused by
        
        genetic predisposition
        
        Infection by a virus
        
        Fatty acids are used more as an energy source
        
        Decrease in blood pH LEVEL
  - - - increases
        
        blood glucose level
        
        Absorption of glucose in the ileum
      - Conversion of
        
        Glycogen to glucose into liver
      - stimulates
        
        Passege of glucose from cells into blood
        
        Fat breakdown
- - - - Secreted primary at night
      - controlled by
        
        Light/dark cycle
      - functions
        
        Relates to biological rhythms associated with reproduction
      - May cause
        
        Seasonal affective disorder where persons are depressed at onset of winter
  - - - contributor to
        
        Feelings of well-being and happiness
      - increases
        
        sexual desire
      - slowest or absent
        
        During sleep
- - - - Primary lymphoid organ of the immune system
- - - - seen in
        
        🔹Saprophytic organism (bacteria, mold, fungi)
        
        🔹insectivorous plants
        
        🔹all animals with coelenterates to mammals
      - by the enzymes
        
        Polymers broken down into monomers
    - - food
        
        phagocytosis
        
        food vacuole
        
        hydroltic
        
        Iysosomes
        
        Golgi complex
  - - - Chemical Digestion
        
        As food is chewed, it is mixed with saliva
        
        secreted into the mouth by three pairs of salivary gland
      - Mechanical Digestion
        
        teeth
        
        Food is broken into small pieces
        
        provides
        
        a large surface area for the action of digestive enzymes in saliva
    - - bollus
        
        📌tastes and shape the food into a ball
      - 📌moves it toward the pharynx
    - - Amylase enzyme in saliva breaks down starch and glycogen molecules into maltose and dextrin
        
        Digestive of carbohydrates(in Mouth):
        
        🔺Strach or Glycogen + Water
        
        amylase
        
        Maltose + Dextrin
        
        Dextrin: Small polypeptide
  - - - begins as a voluntarily action (upper part)
      - continues involuntarily(lower part)
    - - Wawe like motion that move food along the digestive tract
  - - - gastric juice
        
        converts
        
        a meal to acid chyme
        
        stomach releases acidic chyme into the small intestine
        
        📌In adult the stomach produce 2-3 liters of gastric juice each day
    - - secretes
        
        mucus 🔹
        
        protect
        
        the stomach lining
        
        against
        
        HCl and pepsin
        
        hydrochloric acid (HCl)🔹
        
        stomach activates
        
        pepsin
        
        starts
        
        chemical digestion of proteins
        
        1 more item...
        
        inactive form of pepsinogen
        
        protect
        
        1 more item...
        
        pepsinogen(inactive) + HCl
        
        pepsin(active enzyme)
        
        protein digestice enzymes🔹
        
        pepsinogen
        
        activated by HCl
        
        rein
        
        present in
        
        gastric juice
    - - 🔸Hormonal Effect
        
        Gastrin hormone
        
        stimulate
        
        secretion of digestive enzymes from secretory cells
        
        released from G cells
      - 🔸Neural Effect
        
        Taste and smell of food
        
        stimulate
        
        brain
        
        stimulate
        
        stomach
        
        1 more item...
  - - - 🥈Jejenum
      - 🥉Ileum
      - 🥇Duedonum
    - - 📌Chemically digest food into small molecules
      - 📌Absorb molecules into body
      - 📌Fat, carbohydrates and proteins digestion completed in here
    - - chemical digestion is accomplished with the aid of enzymes and other digestive secrations from 3 sources
        
        The Pancreas
        
        When chyme arrives small intestine
        
        small intestine secretes hormones
        
        stimulate
        
        acinar cells
        
        1 more item...
        
        The cells of the small intestine
        
        produce
        
        enzymes
        
        complete carbohydrate and protein digestive
        
        The Liver
        
        produce
        
        🔹Bile
        
        stored in
        
        The gallbladder
        
        2 more items...
        
        consist of
        
        🔸water
        
        🔸bile salt
        
        🔸bilirubin
        
        🔸cholesterol
        
        🔸sodium bicarbonate ions
        
        ❗️responsible for mechanical digestion for lipids❗️
        
        enters duodenum
        
        via
        
        1 more item...
        
        Red blood cell
        
        During embryonic stage
        
        Heparin
        
        prevents
        
        clotting of blood in vessels
        
        stores of
        
        fat-soluble vitamins
        
        D
        
        A
        
        K
        
        E
        
        Glycogen
        
        Iron
        
        regulate
        
        🌡body temperature
        
        by producing heat
        
        📌Largest organ
        
        ✔️Weighting about 1.5 kg
        
        📌Located in abdomen
        
        below the diaphragm
        
        📌Divided into two lobes left and right
        
        📌Blood coming into liver from two vessels
        
        Liver cells receive double supply of blood 🩸
    - - 📌Folds of the intestinal lining
      - 📌Fingirlike projections called villi
      - 📌Tiny projections of the surface of intestinal cells called microvilli
  - - - Colon
        
        absorb
        
        water
        
        feces
        
        became more solid as they move trough the colon
        
        Wastes of the digestive trac
      - Cecum
        
        🔺connects where small and large intestine meet
        
        🔺first 6 cm part
        
        🔺appendix is found at the end
      - Rectum-Anus
        
        last 15 cm part
        
        feces pass trough the rectum
        
        exit via anus
        
        Two sphincters between the rectum and anus controls
        
        bowel movements
    - - Cells of large intestine
        
        secrete
        
        mucus
        
        lubricates the drying mass of the undigested food residue
      - Absorb of vitamin B and K
      - Absorb water and electrolytes
        
        sodium, chlorine, potassium
- - - - consist of
        
        Bone cells (osteocytes)
        
        live in matrix of flexible protein fibers and hard calcium salts and are kept alive by blood vessels, hormones, and nerves
        
        📌Osteocytes
        
        maintain the mineral concentration of the matrix
        
        via the secretion of enzymes
        
        📌Osteoclasts
        
        esponsible for bone resorption
        
        📌Osteoblasts
        
        responsible for forming new bone
        
        Osein (matrix)
        
        made up of inorganic salts, water and organic materials
      - Compact Bone
        
        Very dense and strong
        
        Found in
        
        📌the outside of all our bone
        
        📌middle of long bone
        
        the ground substance of the bon
        
        arranged in concentrated layers around the small canals
        
        which run parallel to the long axis oh the bone
        
        Haversian canals
        
        contain
        
        🔸blood vessels
        
        🔸a nerve
        
        🔸lymph vessels
        
        Haversian canals are interconnected with one other
        
        via
        
        Volkman's canal
        
        Spongy Bone
        
        📌There is no Haversian canal system
        
        Main function
        
        synthesis of blood cells by red bone marrow found its cavities
        
        📌Also known as cancellous bone or trabecular bone
        
        contains
        
        Red bone marrow
        
        📌Usually located at the ends of the long bones
        
        provides
        
        balance to the dense and heavy compact bone
        
        by making bones lighter so that muscles can move them more easily
    - - Chondrocytes
        
        secrete
        
        glycoproteins and collagen
        
        made up most of the matrix of cartilage
        
        called chondrin
      - 📌No blood vessels and nerves
      - 📌Covers the ends of bones at joints
      - 📌Supports the flexible portions of the nose and ears
      - Has three types
        
        Elastic Cartilage
        
        🔺The matrix is semi-opaque
        
        🔺Contains elastic fibers
        
        🔺More elastic than hyaline cartilage
        
        located in
        
        external ear
        
        eustachian tissue
        
        the epiglottis
        
        cartilages of pharynx
        
        Hyaline Cartilage
        
        🔹Has collagen fibers
        
        🔹The matrix is semi-transparent
        
        🔹Resistant to pressure
        
        located in
        
        🔸at the ends of the bone
        
        🔸nose
        
        🔸windpipe
        
        🔸bronchi
        
        🔸skeleton of embryos
        
        Fibrious Cartilage
        
        contains cartilage ground substance and chondrocytes
        
        found in
        
        discs between vertebrae and ligaments
    - - Connection between two or more bones
      - There are three types of joints
        
        Immovable Joints
        
        No movement between bones
        
        found in
        
        skull
        
        Slightly Movable Joints
        
        bone has cartilage and shows slight movement
        
        found in
        
        Joints between the bones vertebral column and neck
        
        Movable(synovial) Joints
        
        The joints are surrounded by a capsule
        
        which is lines with synovial membrane
        
        that produces synovial fluid
        
        found in
        
        🔹wrist
        
        🔹ankle
        
        🔹knee
        
        🔹neck
        
        The bones attached to each other
        
        by
        
        ligaments
  - - - 📌Longer than they are wide
      - 📌Compact bone is outside, spongy bone inside
      - consists several parts
        
        Epipysis
        
        Form of the larger rounded ends of long bones
        
        Diaphysis
        
        This is long central shaft
        
        Epiphyseal plates
        
        Plates of cartilage
        
        Allows the long bones to grow in length during childhood
        
        Periost
        
        Membrain that covers the bone
        
        Rich in blood vessels and nerves
        
        controls
        
        growth
        
        regeneration of the bone
      - Found in
        
        fingers and toes
        
        arms
        
        legs
    - - As tall as tehey are wide
      - Found in
        
        🔸tarsal(ankle)
        
        🔸carpal(wrist)
    - - They are flat and thin
      - Found in
        
        sternum
        
        ribs
        
        skull
      - These bones have 2 plates of compact bone with a layer of spongy bone inside
    - - Have no regular shape and resistant to pressure
      - Found in
        
        skull
        
        vertebrea
        
        jaw
        
        hip
- - - - the heart
        
        that keeps the blood circulating
    - - blood
        
        that serves as a medium of transport
    - - blood vessels
        
        that conduct the blood throughout the body
  - - - 🔸cone-shaped organ
      - located in
        
        thoracic cavity
        
        between the lungs
        
        protected by the sternum
      - 🔸divided in 4 chapter
        
        atria
        
        upper thin-walled chambers
        
        ventricles
        
        thick-walled chambers
      - has three layers
        
        Percardium
        
        Outermost layer
        
        It has 2 thin fibrous protective layers
        
        that contains
        
        fluid
        
        for protect men from friction
        
        Myocardium
        
        Middle layer
        
        Thicker than other layers
        
        Made up of cardiac muscle
        
        Endocardium
        
        Innermost layer
        
        Smooth and single layer
        
        Don't blood vessels
    - - Atrioventicular valves(AV)
        
        allow blood to flow
        
        from
        
        atria
        
        into
        
        ventricles
        
        In the right side of the heart
        
        Tricuspid valve
        
        In the left side of the heart
        
        Bicuspid valve
        
        Semilunar valves
        
        allow blood to move from ventricles into the pulmonary artery and aorta
        
        They prevent back flow from these arteries into the vertices
  - - - During diastole
        
        blood flow from veins into chambers
      - During systole
        
        blood flow from atria into ventricles
    - - 🔹Both ventricles contract and pump blood into the arteries that exit the heart
      - 🔹All chambers relax briefly before the cycle repeats
      - 🔹Both atria contract and pump blood into the ventricles
    - - 1) An electrical signal from the SA starts atrial contraction
      - 2) The electrical signal spreads through the atria causing Tham to contract
      - 3) The signal enters the AV which transmits it to the AV bundle with a slight delay
      - 4) The signal travels through the AV bundle branches to the base of the ventricles
      - 5) Purkinje fibers transmit the signal to ventricular cardiac muscle cells,
        causing contraction from the base upward
  - - - Blood with low oxygen
        
        enters
        
        the right atrium and flow
        
        into
        
        right ventricle
        
        pumps it through
        
        1 more item...
    - - begins in
        
        left ventricle
        
        blood is pumped into the
        
        aorta
        
        blood enters from left atrium
- - - - held together by connective tissue
  - - - allt he muscle fibers of that motor unit will contract at the same time
        
        Each muscle fiber either contracts completely or not at all
        
        all or none response
    - - depends on
        
        the number of motor units
        
        stimulated at on time
  - - - 🔸Moves the skeleton appears striped
      - 🔸All skeleton muscle is under voluntary or conscious
      - 🔸Produce contractions ranging from quick twitches to powerful, sustained tension
      - consist of
        
        bundle of long fibers
        
        each a single cell
        
        running parallel to the length of the muscle
        
        each muscle fiber it self a bundle of smaller myofibrils arranged longitudinally
        
        The myofibrils are composed to two kinds
        
        Thin filaments
        
        consist of
        
        2 more items...
        
        Thick filaments
        
        staggered arrays of myosin molecules
        
        1 more item...
      - They are red because
        
        myoglobin
        
        stores
        
        oxygen in muscle cells
        
        is present in the sarcoplasm of the cells
      - Tendon
        
        A heavy band of fibrous connective tissue
        
        Attaches each end of the muscle to a different bone
      - controlled by
        
        somatic nervous system
        
        action is voluntary
      - contraction
        
        rapid
        
        they became fatigued
      - perform
        
        anaerobic respiration
        
        during vigorous exercise
        
        may cause
        
        lactic acid accumulation
        
        lactic acid fermentation
    - - 📌not striated
      - 📌surrounds large blood vessels
      - 📌action is involuntarily
      - 📌control by
        
        automic nerveous system
      - 📌most hollow organs
      - 📌Does not fatigue
    - - located
        
        only in heart
      - 🔹it is striated
      - 🔹action is involuntarily
      - 🔹initiates its own contractions by SA node
      - 🔹Does not fatigue
  - - - called
        
        sarcomere
        
        bordered by
        
        Z line
    - - made up of
        
        the portion that incudes only actin proteins
    - - lenght of one myosin protein
    - - made up of
        
        myosin protein portion
        
        of A line
    - - 🔹Lenght of sarcomere shorterns
      - 🔹Z lines come closer
      - 🔹I band shorten
      - 🔹H zone reduced or disappear
      - 🔹A band don't change
      - 🔹Lenght of muscle bocames shorter but thicker
        
        no chance in mass and volume of muscle
- - - - helps
        
        maintenance of homeostasis
      - regulate
        
        blood pH
        
        concentrations of sodium, potassium chlorine etc. in blood plasma
      - produce
        
        erythropoietin hormone for RBC production
      - collect
        
        water and filter
      - providing
        
        osmoregulation
        
        regulation of both fluid snd salt content of the body
  - - - Kindeys
        
        Blood enters each kidney through the renal artery
        
        after the blood has been filtered
        
        it exit through the renal vein
        
        Urine
        
        leaves
        
        1 more item...
        
        has
        
        2 more items...
      - Ureters
        
        muscular tube
      - Bladder
        
        linned with smooth muscle
        
        capable of considerable expansion
      - Urethra
  - - - Medulla
        
        made up
        
        collecting ducts
        
        carry
        
        filtrate
        
        to the
        
        1 more item...
      - Pelvis
        
        connect to
        
        ureter
      - Cortex
        
        blood filtered in here
    - - the wastes
        
        of cellular metabolism from blood
    - - the concentrations
        
        of the substances
        
        found in the body fluids
      - pH of blood
  - - - Additional wastes are actively transported into the proximal and distal tubules from the blood
    - - Water, nutrients and wastes are filtered from the glomerular capillaries into the Bowman's capsule of the nephron
    - - In the proximal tubule, most water and nutrients are reabsorbed into the blood
  - - - Bowman's capsule
      - The glomerulus
- - - - Spermatogenesis
        
        production of
        
        sperm
      - Oogenesis
        
        production of
        
        egg
  - - - contains
        
        follicles
        
        consist of
        
        developed egg
        
        oocyte
        
        develops egg
        
        1 more item...
    - - provides
        
        egg cell
        
        from the follicle
        
        produce estradiol
        
        follicular tissue grows within the ovary
        
        corpus leteum
        
        secretes
        
        2 more items...
        
        travels from the ovary to the uterus
        
        via
        
        oviduct
        
        cilia
        
        1 more item...
    - - occur about every 28 days
      - anterior pituitary
        
        secrete
        
        FSH
        
        starts
        
        growth of a follicle
        
        Ovulation
        
        after ovulation
        
        1 more item...
        
        LH
  - - - scrotum
      - penis
    - - testes
        
        produce
        
        sperm
        
        form in
        
        seminiferous tubules
        
        hormones
        
        leading cells
    - - produce
        
        semen
    - - FSH
        
        promotes
        
        the activity of Sertoli cells
        
        nourish developing sprem
      - LH
        
        regulates
        
        Leyding cells
        
        secrete
        
        testosterone
        
        regulates
        
        1 more item...
- - - - targets
        
        antigens
      - carried out by
        
        lymphocytes
        
        such as
        
        B-cells
        
        providing
        
        active immunity
        
        produce
        
        antibodies
        
        2 more items...
        
        create the
        
        antibody mediated response
        
        1 more item...
        
        T-cells
        
        help
        
        T-cells
        
        1 more item...
        
        can be
        
        Cytotoxic T-cells
        
        1 more item...
    - - targets
        
        any invader
      - consist
        
        Symbiotic Bacteria
        
        Gastric Juice
        
        Skin
        
        Antimicrobial Proteins
        
        Cilla
    - - include
        
        Phagocytes
        
        Natural Killer Cells
        
        Inflammatory response
        
        involves
        
        Basophils release histamine
        
        causes
        
        vasodilation
        
        1 more item...
        
        Interferons
        
        Complement Proteins
  - - - breast milk serum
- - - - assist neuronal function by
        
        Providing nutrients
        
        Regulating the composition of the extracellular fluid
        
        Modulating communication between neurons
        
        peeding up the movement of electrical signals
      - have numerous functions
        
        Oligodendrocytes
        
        form the myelin sheaths around axons
        
        Schwann cells
        
        Microglia
        
        protect
        
        nervous system
        
        from
        
        microorganisms
        
        Astrocytes
        
        provide
        
        structural support for neurons
        
        regulate extracellular ions and neurotransmitters
        
        Ependymal cells
        
        Promote circulation of cerebrospinal fluid
        
        Radial glia
        
        play a role
        
        in the embryonic development of the nervous system
    - - receive, process, and transmit information
      - functions
        
        process
        
        information
        
        recieve information
        
        from the environment
        
        produce
        
        elerical signals
      - parts
        
        Dendrites
        
        A cell body
        
        An axon
        
        Synaptic terminals
        
        synapses
      - Types of neurons depending on their functions;
        
        Association (inter) neuron
        
        smaller than sensory and motor neurons
        
        connects sensory and motor neurons and integrate the information
        
        Motor (efferent) neuron
        
        Sensory (afferent) neuron
        
        message travels towards CNS
        
        cell body is outside CNS in Ganglia
  - - - spinal cord and brain
        
        protect
        
        from physical damage
        
        has three part
        
        Dura-mater
        
        Arachnoid mater
        
        Pia mater
        
        consist of
        
        Gray matter
        
        Whitematter
    - - sensory information, generates thoughts, and directs responses
    - - made up of
        
        water, protein, lipid, carbohydrate and other organic and inorganic compounds
      - have 3 main parts
        
        The midbrain
        
        contains
        
        clusters of neurons that contribute to movement, arousal and emotion
        
        related with
        
        certain optic and auditory reflexes
        
        The forebrain
        
        The cerebrum
        
        consists of
        
        cerebral hemispheres
        
        A thick band of axons called the corpus callosum
        
        corpus callosum
        
        The hindbrain
        
        Pons
        
        Cerebellum
        
        The medulla oblangata
    - - extends from
        
        base of the brain to the lower back
      - controls many reflexes and conducts(conveys) information to and from the brain to the PNS.
  - - - information to and from the CNS
    - - originate in the brain and mostly terminate in organs of the head and upper body
    - - originate in the spinal cord and extend to parts of the body below the head
    - - controls voluntary movement.
      - Motor neurons of the somatic nervous system form synapses with skeletal muscles and control voluntary movement
    - - controls involuntary actions
      - Motor neurons of the autonomic nervous system innervate the heart, smooth muscles, and glands, and produce involuntary actions.
      - Sympathetic Division
        
        The neurons of the sympathetic division release the neurotransmitter norepinephrine onto their target organs, preparing the body for stressful or energetic actions.
      - Parasympathetic Division
        
        The neurons of the parasympathetic division release acetylcholine onto their target organs.
        
        he parasympathetic division controls maintenance activities that can be carried out at leisure, often
        called “rest and digest”.
- - - - cleans, moistens and warmth the incoming air
    - - consist of two elastic tissue
        
        vocal cord
        
        strerch across airway
    - - conteins
        
        smooth muscle
        
        cartilage
      - splits into two bronchi
        
        each brunches branches into small tubes
        
        broncioles
        
        lead to
        
        alveoli
        
        gas exchange occurs
    - - there are two lung
        
        right lung
        
        has three lobes
        
        left lung
        
        has two lobes
        
        surrounded by
        
        pleura
    - - tiny air sacs in the lungs
      - gas exchange occurs
        
        O2 diffuses into the blood
        
        CO2 difuses out of the blood
      - wall of alveoli
        
        consist of
        
        single thin layer
  - - - occurs when
        
        muscles of diaphragm are contracted
        
        chest cavity expands, volume increase
        
        pressure around the lungs decrease
        
        air is drawn into respiratory trac
    - - occurs when
        
        muscles of diaphragm are relaxed
        
        pressure around the lungs increase
        
        chest cavity contracts, volume decrease
        
        air is forced out of the respiratory trac
    - - breathing centre
        
        controlled by
        
        automatic mechanism
        
        located in
        
        medulla oblangata
        
        send impulse to
        
        rib muscles
        
        stimulating muscles to contract
        
        diaphram