03 A szabályozás
Coordination
Control and regulation
- Control: centre – command – system
- Regulation: centre – command – system – FEEDBACK (positive: increasing is answer to increasing, negative: decreasing is answer to increasing)
Nerve cell: cell body, dendrites, axon, terminal branches, myelin sheath (Schwann cells, protection and feed)
Resting potential
- Sodium-potassium pump: Na+ is pumped out and K+ is pumped in the cell across the cell membrane by active transport
- Potential difference: -70 mV (cytoplasm is partially negative because of Cl- and protein anions)
Action potential
When the neuron is stimulated:
- Depolarisation: Na+ channels open, Na+ ions flood in (+ charge inside of the cell)
- Repolarisation: K+ ions get out (- charge in the cell)
- Overshoot: too many K+ leave the cell, charge gets more negative
- Na+ channels close, sodium-potassium pump restores the resting potential
Progress of the impulse
- Na+ ion moving across the membrane excites the next part of the axon: action potential progresses along the length of the axon
Speed of transmission:
- Unmyelinated axons: 1-3 m/s
- Myelinated axons: up to 100 m/s
Saltatory conduction: myelin sheath insulates the axon – action potential occurs only in Ranvier-nodes (between the Schwann-cells)
The synapse
- Where two neurons functionally meet
Parts:
- Presynaptic membrane
- Synaptic cleft (gap)
- Postsynaptic membrane
Electric synapse:
- gap 2-3 nm (conducts in 2 directions)
Chemical synapse:
- vesicles with neurotransmitters, receptors can detect the neurotransmitters on the postsynaptic membrane - 1 direction
- Gap: 20-30 nm, slower conduction
- Neurotransmitters: acetylcholine, noradrenaline (excitatory synapse), gamma-amino-butter-acid (GABA) (inhibitory synapse)
Reflex
- Receptor
- Sensory neurone
- Centre (relay neurone)
- Motor neurone
- Effector
- Feedback from the effector to the centre
- Centre regulates the sensitivity of the receptor
Nervous system
Classification by structure:
- Central nervous system: brain, spinal cord
- Peripheral nervous system: nerves, receptors, ganglia (s. ganglion)
Classification by operation:
- Somatic nervous system: controls voluntary muscle system
- Autonomic nervous system: controls visceral functions (digestion, breathing, excretion, etc.)
- Sensory functions: eyesight, hearing, smelling, etc.
Spinal cord
- In the vertebral column (spinal canal)
Spinal meninges: protecting layers
- Dura mater
- Arachnoid mater
- Pia mater
Cerebrospinal fluid: Central nervous system „floats” in it
Sections:
- Cervical
- Thoracic
- Lumbar
- Sacral (cauda eqiuna, „horse tail”)
Cross section
- Central canal
- White matter: myelinated axons
- Grey matter: cell bodies
- Dorsal root: sensory neurons
- Ventral root: motor neurons
- Dorsal ganglion: sensory neuron cell body
Spinal reflexes
- Visceral reflex: visceral receptor – sensory neuron - spinal-cord – motor neuron – ganglion in the peripheral system - effector
- Somatic reflex: Sensory neuron – relay neuron in the spinal cord – motor neuron
- Skin reflex: Sensory neuron in the skin – relay neuron in the spinal cord – motor neuron in the muscle
Brain
- Meninges: like on the spinal cord
- Forebrain (előagy):
- Cerebrum (nagyagy)
- Diencephalon (interbrain) (köztiagy)
- Thalamus
- Hypothalamus
- Midbrain (középagy)
- Hindbrain (utóagy):
- Pons (híd)
- Medulla oblongata (nyúltvelő)
- Cerebellum (kisagy)
- Brainstem: midbrain, pons, medulla oblongata
Brainstem
- Structure: „brainstem reticular substance” (no white and grey matter)
- Nuclei (groups of neurons in the central system)
- Nerve fibres
- Control of nerves:
- Sensory: dorsal side
- Motor: ventral side
Functions of the brainstem
Midbrain:
- Control of sleeping/wakefulness
- Coordination of muscle tone, bearing, balancing, walking
Autonomic centres:
Medulla oblongata:
- Reflexes of nutrition (chewing, swallowing)
- Breathing in/out center
- Blood pressure coordination center
- Coughing, sneezing, vomiting centres
Pons:
- Breathing stimulating/inhibiting
Diencephalon (interbrain)
Hypothalamus: autonomic tasks
- Control of the body temperature
- Food intake centre (hunger, thirst)
- Control of the endocrine system
- Emotional and sexual functions
Thalamus:
- Control and analysis of sensory functions
Cerebrum
- 2 hemispheres, connected by corpus callosum
- Lobes: frontal, parietal, occipital, temporal
- White matter: nerve fibres (inside) – nuclei (sing.: nucleus)
- Grey matter: Cell bodies (outside) – CEREBRAL CORTEX (agykéreg)
Structure of the cortex
- 90 % of the neurons (9 thousand million cells!)
- Large surface area (2200 cm2), folded surface
- 6 layers
- Columns (functional units of the cortex): 5000 neurons (500 pyramidal cells)
Limbic system: surrounding the corpus callosum
- Inner circle: learning, memory
- Outer circle: autonomic functions (hypotalamo-limbic system)
Cerebellum
- Grey and white matter
- Control of complicated, fast moving
Peripheral nervous system
Spinal nerves: from the spinal cord (31 pairs)
- dorsal and ventral root and nerve
- sensory, motor and autonomic fibres
Brain nerves
- 12 pairs
Sensory functions
Receptors: an environmental effect can induce action potential
Adequate stimulus: threshold of stimulus is the lowest
- Photoreceptor: light
- Mechanoreceptor: touch, pressure
- Thermoreceptor: heat, cold
- Chemoreceptors: taste, odour
Eye
Parts of the eye:
- Cornea, aqueous humour, iris, pupil
- Ciliary body, suspensory ligaments, lens, vitreous humor
- Sclera, choroid, retina, fovea, blind spot, optic nerve
Receptors in the retina:
Rod:
- Detects the presence of light
- Very sensitive (1 photon)
- Located mainly in the peripheral areas of the retina
Cone:
- Detects colours (red, green, blue)
- Not so sensitive (5-7 photons)
- Located mainly in the fovea
Focusing (accomodation)
- Light rays are refracted to focus onto the retina by the cornea, aqueous humour, lens and vitreous humour
- Lens can change its shape: amount of refraction changes
- Viewing close objects: ciliary muscles contract – lens is more spherical – object is focused to the retina
- Distant objects: ciliary muscles relax – lens is thin
Iris
- Regulates the amount of light entering the eye:
- Bright light: circular muscles contract – pupil is constricted
- Dim light: radial muscles contract – pupil is dilated
Stereo vision: two eyes – different points of view – distance can be detected
Vision centre: occipital lobe
Hearing
- Sound: longitudinal wave (frequency, wave length)
Outer ear:
- Auricle (pinna): collects and amplifies the sound waves
- Ear canal: leads waves to the
- Eardrum (tympanic membrane): vibrates
Middle ear
- Ear ossicles: hammer, anvil, stirrup (transmit vibrations to the inner ear)
- Eustachian tube: equalizes the air pressure on either side of the eardrum
Inner ear:
- Oval window
- Cochlea: fluid-filled spiral tube. Organ of Corti: hair cells (receptors) detect the vibration of sounds with different frequencies – sound interference)
- Round window: dampener of the vibration („exit”)
Balance
- Inner ear:
- Saccule, utricle: CaCO3 crystals press the receptors in the wall – sense of position
- Semicircular canals( 3 in 3 directions): hair cells can detect the movement of the fluid – sense of movement
Taste:
- Receptors on the taste buds (tongue)
- Tastes: sweet (on the tip), salted, sour (aside), bitter (back side)
Smell:
- Receptros in the olfactory epithelium (nasal cavity)
- Smell and taste are usually linked (zamat)
Sensation of the skin
- Mechanical (pressure, touch), thermo- (cold, warm), pain receptors
- Crossing at the spinal cord or the medulla oblongata
- Relay at the thalamus
- Sensory area of the cortex: front region of the parietal lobe
Helath of sensory organs
Eye:
- Pink eye (connectivitis): reddish eye, itch
- Stye: inflammation of the sebaceous gland in the eyelid
- Crossed eye (strabismus): disfunction of extraocular muscles or problems in refraction (double vision)
- Astigmatism: refrection is irregular
- Glaucoma: pressure of the aqueous humor increases (surgery)
- Cataract: lens is not transparent (műtét)
- Nearsightedness: axis of the eye is longer than normally (biconcave lens in eyeglasses)
- Farsightedness: axis of the eye is shorter than normally (biconvex lens in eyeglasses)
- Old age farsightedness : lens becomes less flexible
- Color blindness: problem of receptors
- Night blindness: deficiency disease of vitamin A
- Retinal detachment: retina separates the choroid
Ear:
- Otitis externa (swimmer’s ear): inflammation of ear canal
- Otitis media: inflammation of middle ear
- Hearing loss: partially or totally (deafness)
Motor functions
- Neuromuscular synapse: modified axon end connects to the skeletal muscle
Motor cortex: posterior part of the frontal lobe
Pyramidal system: leads from the motor cortex to the muscles, crosses the pyramid uninterrupted– voluntary movements, quick start of learnt activities
Extrapyramidal system: passes by the pyramid, undergoes a lot of syneapses – rough motor actions, learnt movements, muscle tone
Autonomic/vegetative nervous system
Control of visceral organs
- Sympathetic system: katabolism is stimulated, energy sources are mobilised (pulse, blood sugar level, blood pressure, breathing rate increases, „fly and fight” (brain and muscle blood vessels dilate, skin and digestive system vessels contract)
- Parasympathetic system: anabolism is stimulated to gain and conserve energy at rest
Vegetative centres: brainstem
Human behaviour
Inherited and learnt components
Lymbic system:
- Outer circle: vegetative control, innate and emotional reactions,effects on hormone system
- Inner circle: filtering of stimuli, memory
Health of the nervous system
Drugs: addictive substances
- Stimulants (koffein, teobromin), narcotics (alcohol, illegal drugs), depressants (sleeping pills), analgesics (pain relivers)
Diseases:
- Depression
- Stress
- Schizpophrenia
- Headache
- Migraine
- Stroke
- Thrombosis
- Epilepsy
- Cerebral concussion
- Paralysis
- Lumbago
- Meningitis
Hormonal regulation
Hormone:
- Chemical messenger molecules
- Produced by cells, tissues or endocrine glands
- Acts on target organs
Control of hormone system:
Neuroendocrine system: hormone system is under control of the nervous system (feedback)
Hypophysis (pituitary gland)
- Connects to the hypothalamus by a stalk
- Controls all other neuroendocrine glands
Anterior lobe:
Is controlled by the hypotalamus by neurosecretums
Hormones:
Growth hormone (STH, GH):
- Increases blood sugar level, stimulates growing of bones and cartilages
- Hyposecretion: hypophysal dwarfism
- Hypersecretion: in childhood: gigantism, in old age: acromegaly
Thyrotropic hormone (Thyroid stimulating hormone, TSH)
Adrenocorticotropic hormone (ACTH)
Follicle stimulating hormone (FSH)
Luteinizing hormone (LH): controls hormone production of the yellow body
Prolactin (LTH): controls breast milk production
Posterior lobe
Is formed by axons of the hypothalamus
Hormonjai:
Oxytocin: stimulates the contraction of smooth muscle cells in the uterus (labour) and breasts (milk elimination)
Vasopressin (antidiuretic hormone, ADH): stimulates the reabsorption of water from the primary filtrate in kidneys
Thyroid gland
In front of the larynx
Hormones:
Thyroxin (and triiodothyronine):
- iodine-containing amino acide
- Increases the biological oxidation
- Helps development in cooperation with the growth hormone
- Hyposecretion: goitre (enlarged thyroid gland), in adults myxoedema (mental and physical sluggishness), in childhood cretenism (physical and mental underdevelopment)
- Hipersecretion: fast metabolism, Basedow disease
Kalcitonin: produced by the connective tissue of the thyroid gland, decreases the calcium ion concentration of blood
Parathyroid glands
Embedded in the thyroid
- Parathormone: increases the calcium ion concentration of blood for normal nervous and muscle activity by stimulating absorption and reapsorption of calcium, vitamin D is necessary.
Adrenal glands
- on the top of kidneys
Adrenal cortex:
- Mineralocorticoids (stimulate sodium ion reabsorption in kidneys)
- Glycocorticoids (increase blood sugar level)
- Sex hormones (mainly malei n both sexes)
Adrenal medulla:
- Adrenaline: stress hormone (sympathetic reaction)
- Noradrenaline, dopamine
Pancreas
Islets of Langerhans
- Insulin: decreases the blood sugar level (stimulates cellular sugar uptake and storage)
- Glukagon: increases the blood sugar level (stimulates glycogen-glucose transformation in liver cells
- DIABETES: less amount or lack of insulin
Gonades
Testicle
Testosterone: controls development of sexual organs and secondary characteristics, maintains the production of sperm cells
Ovary:
Oestrogen: produced by the follicle, stimulation of sexual development, stimulates the regeneration of the mucous layer of the uterus after menstruation
Progesterone: produced by the yellow body, maintains the thickened mucous epithelium of the uterus
Az érzékszervek egészsége
Szem:
- Kötőhártyagyulladás: szempirosság, viszketés
- Árpa: faggyúmirigy gyulladása
- Kancsalság: szemmozgató izom működési zavara v. fénytörési hiba (kettőslátás!)
- Asztigmia: szabálytalan fénytörés („cilinderes” szemüveg)
- Zöldhályog: csarnokvíz nyomása megnő (műtét)
- Szürkehályog: átlátszatlan szemlencse (műtét)
- Rövidlátás: hosszabb szemtengely (szórólencse)
- Távollátás: rövidebb szemtengely (gyűjtőlencse)
- Öregkori távollátás: lencse rugalmatlanná válik
- Színtévesztés, színvakság: receptorhiba
- Farkasvakság: A vitamin hiánya (rodopszin nincs elég)
- Retinaleválás: ütés miatt vakság
Fül:
- Hallójáratgyulladás, középfülgyulladás
- Nagyothallás: dobhártya sérülése, izmok elöregedése
Mozgatóműködés
- Ideg-izom szinapszis M142.1
Mozgatóközpont: homloklebeny hátsó része
Piramisrendszer: átkapcsolódás nélkül fut a piramison keresztül – pontos és finom mozgások irányítója és mozgások beindítója
Extrapiramidális pálya: többször átkapcsolódik, elkerüli a piramist – durvább mozgások és megtanult mozgások irányítása
Vegetatív idegrenszer
A belső szervek működését irányítja
- Szimpatikus idegrendszer: aktiválja a tartalékokat – védekezés
- Paraszimpatikus: tartalékok felhalmozása (M 146.1)
Vegetatív központok. Agytörzs
Légzés szabályozása:148.1
Emberi magatartás
Öröklött magatartásformák és tanult elemek
Limbikus rendszer:
- Külső kör: vegetatív szabályozás, ösztönös és érzelmi reakciók szabályozása
- Belső kör: szűrés, memória
Tanulás, emlékezés, beszéd
Idegrendszer egészsége
- Izgatószerek (koffein, teobromin), narkotikumok (alkohol, kábítószerek)
Betegségek:
- Depresszió
- Stressz
- Tudathasadás
- Fejfájás
- Migrén
- Agyvérzés
- Agytrombózis
- Agyérgörcs
- Epilepszia
- Agyrázkódás
- Bénulás
- Lumbágó
- Agyhártyagyulladás
Hormonális szabályozás
Hormon:
- „Kémiai hírvivő molekula”
- Sejt, szövet, belső elválasztású mirigy termeli
- Befolyásolja az életműködéseket
A hormonrendszer szabályozása:
Neuroendokrin rendszer: a hormonrendszer az idegrendszer irányítása és kontrollja alatt működik
- Negatív visszacsatolás M159.2
Agyalapi mirigy
A hipotalamuszhoz nyéllel kapcsolódik
Elülső lebeny:
A hipotalamusz neuroszekrétumai közvetve szabályozzák
Hormonjai:
Növekedési hormon (STH, GH):
- Serkenti a csont és porcnövekedést, emeli a vércukorszintet
- Hiánya: arányos törpenövés
- Túltermelődés: fiatalon óriásnövés, idős korban akromegália
Pajzsmirigyserkentő hormon (TSH)
Mellékvesekéreg-serkentő hormon (ACTH)
Tüszőserkentő hormon (FSH): tüszőérést serkenti
Sárgatestserkentő hormon (LH): a sárgatest hormontermelését szabályozza
Tejelválasztást serkentő hormon (LTH): tejtermelést szabályozza
Hátulsó lebeny
A hipotalamusz axonjai alkotják
Hormonjai:
- Oxitocin: méh és emlő simaizmok összehúzódása
- Vazopresszin (antidiuretikus hormon, ADH): a vesében a szűrletből a víz visszaszívását serkenti
Pajzsmirigy
A gége előtt
Hormonok:
Tiroxin (és trijód-tironin):
- Jódtartalmú aminosav
- Fokozza a szervezet oxigénfelhasználását és ezzel a biológiai oxidációt
- Együttműködik a növekedési hormonnal, segíti a fejlődést
- Alultermelődés: golyva, strúma, felnőttként myxoedema, gyerekként kreténizmus
- Túltermelődés: felgyorsult anyagcsere, Basedow-kór
Kalcitonin: pajzsmirigy kötőszövetében termelődik, a vér kalciumszintjét csökkenti
Mellékpajzsmirigy
A pajzsmirigybe ágyazódik
- Parathormon: a bélből a Ca-felszívást segíti, a vér Ca-szintjét növeli
- D-vitamin kell a hatásához
Mellékvese
- A vesék csúcsain
Kéregállomány:
- Só- és vízháztartásra ható hormonok (Na-visszaszívás serkentése)
- Szénhidrátanyagcserére ható hormonok (vércukorszint emelése)
- Nemi hormonok (főleg férfi)
Velőállomány:
- Adrenalin: vészreakció
- Noradrenalin, dopamin
Hasnyálmirigy
Langerhans-szigetek
- Inzulin: serkenti a sejtek glükózfelvételét és a glükóz, zsírsavak raktározását
- (DIABETES)
- Glukagon: vércukorszintet növeli
Ivarmirigyek
Here: tesztoszteron
Petefészek: ösztrogén, progeszteron