Explore the Human Body-3

Post Share Embed

Flag

Share on Facebook

Post to Twitter

Join the PMT Medical Entrance Exam Community

Description

The fastest computer in the world is much faster than that and it is sitting right on top of your shoulders! The human brain is an amazing computing device and the fastest processor available right now. Your brain, can understand any number of speakers. It needs no training and will make zero mistakes. It may even be able to understand multiple languages! And the speech processing portion of your brain is just one small part of the whole package -- your brain can also process complex visual images, control your entire body, understand conceptual problems and create new ideas. Your brain is made up of about one trillion cells with 100 trillion connections between those cells. We might take a rough estimate and say it is handling 10 quadrillion instructions per second, but it really is hard to say. Come with me to explore this super machine…

Comments

Would you like to comment?

Presentation Transcript

Slide 1 : Dr Aman Biswas Explore the Human Body - 3

Catch us at …http://bisbio.in 09814016083, 09855516083email … bisbioin@gmail.com or amanbiswas60@gmail.com : Catch us at …http://bisbio.in 09814016083, 09855516083email … bisbioin@gmail.com or amanbiswas60@gmail.com Biology Problems UGC/CSIR NET Life Sciences PMT SAT Advance Program Civil Services Entrance to Biotechnology and Post graduate Sciences

Components of Human machine : Components of Human machine

Slide 4 : There are more nerve cells in the human brain than there are stars in the Milky Way

If we lined up all the neurons in our body it would be around 600 miles long : If we lined up all the neurons in our body it would be around 600 miles long

Slide 6 : Brain is only … 2% of our total body weight

Slide 7 : Brain requires 20% of total body oxygen requirement & 20% of total blood pumped by heart.

Slide 8 : Blockage or rupture of blood vessels leads rapidly to damage or death of cells in the affected region, producing ischemic or haemorrhagic. Cells of affected area die due to nutritional (oxygen and glucose) starvation and metabolite build-up. Dying cells release excitatory neurotransmitters (glutamate) which damages intact cells through Excititoxicity.

Slide 9 : The average weight of a human brain is ________ kg. 1.4 The average brain is 140 mm wide, 167 mm long and 93 mm high.

Who tends to have larger and heavier brain … Man or Woman ? : Who tends to have larger and heavier brain … Man or Woman ? This is just because, usually, men are generally bigger than women - it does not mean there is any difference in intelligence. Some of the most intelligent people in history had smaller than average brains.

Slide 11 : The weight of the brain also changes with age An adults brain is 3 times as heavy as a newborn baby's brain But, after the age of 20, the brain loses 1g in weight every year

Slide 12 : Brain has no pain receptors. Our brain has 400 miles of blood vessels. If blood supply to brain is interrupted for 10 seconds, you will lose consciousness

Slide 13 : 125 ml is CSF CSF pressure is 70 -180 mm Hg

Slide 14 : The brain itself contains more than 1000 billion nerve cells When they are busy these cells generate enough electrical energy to power a lightbulb. Brain produces 25 watts of power.

Slide 15 : You can fit 30,000 neurons on tip of the pin

Slide 16 : Neurons are the largest cells in the human body. Some of the nerve cells that connect the toes with the spinal cord are about 1 metre long.

Slide 17 : Signals travel along nerves at about 360km/h (225mph) Fast enough to travel from your brain to your toe in less than 1/50 of a second.

Slide 18 : Do you know Neurons do not under go mitosis

Slide 19 : The central nervous system is connected to every part of the body by 43 pairs of nerves. Twelve pairs go to and from the brain

Slide 20 : With 31 pairs going from the spinal cord.

How many miles of nerves run through our bodies ? : How many miles of nerves run through our bodies ? There are nearly 45 miles of nerves running through our bodies.

Chemicals of the brain : Chemicals of the brain Neurotransmitter substances are generally classified as low molecular weight (LMW) substances and peptides.

What is a true neurotransmitter? : What is a true neurotransmitter? A substance is synthesized Stored presynaptically Released by appropriate stimuli Produces the expected post-synaptic effect.

Neurotransmitters : Neurotransmitters Several substances meet some, but not all criteria and are regarded as "putative" transmitters Eg. Aspartate Histamine Many peptides

Majority of synapses in the brain are amino-acidergic : Majority of synapses in the brain are amino-acidergic Glutamate (the most prevalent excitatory transmitter) Glycine Gama -aminobutyric acid Aspartate and maybe taurine (inhibitory).

Aminergic and cholinergic groups : Aminergic and cholinergic groups Dopamine, NE, E (catecholamines); 5-Hydroxytryptamine (indolealkylamine) Histamine and Acetylcholine.

Slide 27 : Enzymes catalysing the synthesis of these transmitters are synthesized in the perikarya and carried by slow transport to the axon terminals. The transmitters are synthesized at the synaptic endings and actively transported into the vesicles there.

Postsynaptic Potentials : Neurotransmitter receptors mediate changes in membrane potential according to: The amount of neurotransmitter released The amount of time the neurotransmitter is bound to receptors The two types of postsynaptic potentials are: EPSP – excitatory postsynaptic potentials IPSP – inhibitory postsynaptic potentials Postsynaptic Potentials

Neurotransmitters : Neurotransmitters

Neurotransmitters: Biogenic Amines : Include: Catecholamines – dopamine, norepinephrine (NE), and epinephrine Indolamines – serotonin and histamine Broadly distributed in the brain Neurotransmitters: Biogenic Amines

Slide 31 : Serotonin plays role in emotional behaviors and our biological clock Dopamine involved in Parkinson’s disease & cocaine use

Neurotransmitters : Amino Acids : Include: GABA – Gamma (?)-aminobutyric acid Glycine Aspartate Glutamate Found only in the CNS & not well understood Neurotransmitters : Amino Acids

Neurotransmitters: Peptides : = Neuromodulators (chemically similar to NT’s) Include Substance P – mediator of pain signals Beta endorphin, dynorphin and enkephalins Act as natural opiates, reducing our perception of pain Bind to the same receptors as opiates and morphine Gut-brain peptides Somatostatin cholecystokinin Neurotransmitters: Peptides

Neurotransmitter effects : Neurotransmitter effects Excitatory (depol.) vs inhibitory (hyperpol.) The same NT can be both excitatory to one receptor & inhibitory to another ACh is excitatory at neuromuscular junctions skeletal muscle But is inhibitory when released on cardiac muscle

Sequences of events at cholinergic synapse : Sequences of events at cholinergic synapse

Acetylcholine : Acetylcholine Small-molecule Cholinergic neurons Postsynaptic effect : depends Made from Acetyl CoA and choline Acetylcholinesterase

Acetylcholine receptors : Acetylcholine receptors Nicotinic Muscarinic Ionotropic Metabotropic Muscle CNS & heart Autonomic nervous system

Glutamate : Glutamate Small-molecule Glutaminergic neurons Postsynaptic effect : depends Very important in CNS Synthesized from glutamine from glial cells

Glutamate receptors : Glutamate receptors Ionotropic NMDA late EPSP Glycine & Mg2+ dependent AMPA early EPSP kainate early EPSP Metabotropic

GABA (?-aminobutyric acid) : GABA (?-aminobutyric acid) Small-molecule GABAergic neurons Postsynaptic effect : Inhibitory Made from glucose

GABA receptors : GABA receptors GABAA – Ionotropic gates Cl- channel GABAB – Metabotropic gates K+ channel

Dopamine : Dopamine Biogenic amine Postsynaptic effect : Excitatory or inhibitory

Dopamine receptors : Dopamine receptors Metaobotropic dopamines : 6 kinds Bound by many antipsychotic drugs

Dopaminergic neurons and Parkinson’s : Dopaminergic neurons and Parkinson’s Parkinson’s disease Involuntary tremors loss of power Shuffling gait Balance problems. Caused by dopamine deficiency. Loss of neurons in substantia nigra pars compacta Treatment with L-DOPA

Norepinephrine : Norepinephrine Biogenic amine Formed from dopamine also in PNS sympathetic NS

Norepinephrine receptors : Norepinephrine receptors Effect depends on receptor bound a-receptors ß-receptors

Epinephrine : Epinephrine Biogenic amine synthesized from norepinephrine Effect depends on receptor bound a-receptors ß-receptors

Histamine : Histamine Biogenic amine Postsynaptic effect : Excitatory

Why do some cold medicine make you sleepy? : Why do some cold medicine make you sleepy?

Histamine effects ? : Histamine effects ? Receptors are all G-protein coupled In brain, affects arousal and attention In periphery affects inflamation, vasodilation.

Serotonin : Serotonin Biogenic amines Postsynaptic effect: Excitatory

Serotonin : AKA 5-HT.. 5HT is best known as a transmitter in several brain areas: 1) sleep regions2) limbic system mood control regions3) pain suppression system Serotonin

Serotonin effects : Serotonin effects Involved in sleep/wakefulness cycle Most receptors are metabotropic but one group are ionotropic.

Why does chicken make you sleepy? : Why does chicken make you sleepy? Selective serotonin reuptake inhibitors (SSRIs) are antidepressants that affect serotonin levels in the brain.

Other neurotransmitters : Other neurotransmitters ATP and breakdown products Neuroactive peptides reproductive hormones opioids Digestive hormones Endocannabinoids

Neurotransmitter synthesis : Neurotransmitter synthesis BBIPL Glutamate g-Aminobutyrate Serotonin Tyrosine Tryptophan Amino Acid Precursors

Pathway : Pathway Dopamine Norepinephrine Serotonin (5-HT) Tyrosine Tryptophan Catecholamines DOPA 5HTP Epinephrine

Slide 60 : Disorders related to Neurotransmitters

Slide 62 : The End Thanks For Listening And to the helping hands of Dr. S. Biswas & Wiziq team