Brain

Brain

 

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals—only a few invertebrates such as sponges, jellyfish, adult sea squirts and starfish do not have a brain, even if diffuse neural tissue is present. It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste, and smell. The brain is the most complex organ in a vertebrate's body. In a typical human, the cerebral cortex (the largest part) is estimated to contain 15–33 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.

Anatomy

The shape and size of the brains of different species vary greatly, and identifying common features is often difficult. Nevertheless, there are a number of principles of brain architecture that apply across a wide range of species. Some aspects of brain structure are common to almost the entire range of animal species;others distinguish "advanced" brains from more primitive ones, or distinguish vertebrates from invertebrates.

The simplest way to gain information about brain anatomy is by visual inspection, but many more sophisticated techniques have been developed. Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, and then sliced apart for examination of the interior. Visually, the interior of the brain consists of areas of so-called grey matter, with a dark color, separated by areas of white matter, with a lighter color. Further information can be gained by staining slices of brain tissue with a variety of chemicals that bring out areas where specific types of molecules are present in high concentrations. It is also possible to examine the microstructure of brain tissue using a microscope, and to trace the pattern of connections from one brain area to another.

Here is a list of some of the most important vertebrate brain components, along with a brief description of their functions as currently understood:

• The medulla, along with the spinal cord, contains many small nuclei involved in a wide variety of sensory and motor functions.
• The pons lies in the brainstem directly above the medulla. Among other things, it contains nuclei that control sleep, respiration, swallowing, bladder function, equilibrium, eye movement, facial expressions, and posture.
• The hypothalamus is a small region at the base of the forebrain, whose complexity and importance belies its size. It is composed of numerous small nuclei, each with distinct connections and neurochemistry. The hypothalamus regulates sleep and wake cycles, eating and drinking, hormone release, and many other critical biological functions.
• The thalamus is another collection of nuclei with diverse functions. Some are involved in relaying information to and from the cerebral hemispheres. Others are involved in motivation. The subthalamic area (zona incerta) seems to contain action-generating systems for several types of "consummatory" behaviors, including eating, drinking, defecation, and copulation.
• The cerebellum modulates the outputs of other brain systems to make them precise. Removal of the cerebellum does not prevent an animal from doing anything in particular, but it makes actions hesitant and clumsy. This precision is not built-in, but learned by trial and error. Learning how to ride a bicycle is an example of a type of neural plasticity that may take place largely within the cerebellum.
• The optic tectum allows actions to be directed toward points in space, most commonly in response to visual input. In mammals it is usually referred to as the superior colliculus, and its best-studied function is to direct eye movements. It also directs reaching movements and other object-directed actions. It receives strong visual inputs, but also inputs from other senses that are useful in directing actions, such as auditory input in owls and input from the thermosensitive pit organs in snakes. In some fishes, such as lampreys, this region is the largest part of the brain.The superior colliculus is part of the midbrain.
• The pallium is a layer of gray matter that lies on the surface of the forebrain. In reptiles and mammals, it is called the cerebral cortex. Multiple functions involve the pallium, including olfaction and spatial memory. In mammals, where it becomes so large as to dominate the brain, it takes over functions from many other brain areas. In many mammals, the cerebral cortex consists of folded bulges called gyri that create deep furrows or fissures called sulci. The folds increase the surface area of the cortex and therefore increase the amount of gray matter and the amount of information that can be processed.
• The hippocampus, strictly speaking, is found only in mammals. However, the area it derives from, the medial pallium, has counterparts in all vertebrates. There is evidence that this part of the brain is involved in spatial memory and navigation in fishes, birds, reptiles, and mammals.
• The basal ganglia are a group of interconnected structures in the forebrain. The primary function of the basal ganglia appears to be action selection: they send inhibitory signals to all parts of the brain that can generate motor behaviors, and in the right circumstances can release the inhibition, so that the action-generating systems are able to execute their actions. Reward and punishment exert their most important neural effects by altering connections within the basal ganglia.
• The olfactory bulb is a special structure that processes olfactory sensory signals and sends its output to the olfactory part of the pallium. It is a major brain component in many vertebrates, but is greatly reduced in primates.

Mammals

The most obvious difference between the brains of mammals and other vertebrates is in terms of size. On average, a mammal has a brain roughly twice as large as that of a bird of the same body size, and ten times as large as that of a reptile of the same body size.

Size, however, is not the only difference: there are also substantial differences in shape. The hindbrain and midbrain of mammals are generally similar to those of other vertebrates, but dramatic differences appear in the forebrain, which is greatly enlarged and also altered in structure.The cerebral cortex is the part of the brain that most strongly distinguishes mammals. In non-mammalian vertebrates, the surface of the cerebrum is lined with a comparatively simple three-layered structure called the pallium. In mammals, the pallium evolves into a complex six-layered structure called neocortex or isocortex. Several areas at the edge of the neocortex, including the hippocampus and amygdala, are also much more extensively developed in mammals than in other vertebrates.

The elaboration of the cerebral cortex carries with it changes to other brain areas. The superior colliculus, which plays a major role in visual control of behavior in most vertebrates, shrinks to a small size in mammals, and many of its functions are taken over by visual areas of the cerebral cortex.The cerebellum of mammals contains a large portion (the neocerebellum) dedicated to supporting the cerebral cortex, which has no counterpart in other vertebrates.

Cell Structure And Function : Part Three

CELL STRUCTURE AND FUNCTION

Some basic concepts of cell chemistry

The Nature of atom

As we all know that atom is the smallest compound identity of any type of matter present in the universe. The nature of atom is always same for every fundamental biological or physical unit only the characteristics of the atom differ. Atom is further divided into three fundamental particles namely proton, neutron and electron.

Chemical bonds

Chemical bond is a simple structure of binding of atoms and molecules which forms the skeletal structure of matter. Bond is nothing but a shared electron or electrons which bind two atoms or molecules.

There are three types of bonds on basic field of classification but there are only two of them in our concern

1)   Covalent bond

The bond in which a pair of electron is shared by the atoms is called a covalent bond this can be explained by a simple example of the two atoms of hydrogen molecule. Although both the atoms are electrically neutral but at very close range negatively charged electron of both the atoms are attracted towards the positively charged core of both the atoms resulting in sharing of valence electrons to maintain the balance of electromagnetic forces. Now if there are two pairs of shared electrons it is termed as double covalent bond and the very case is involved in three shared pair namely triple covalent bond. In the covalent bond of the two H atoms of H₂, the electron pair is shared equally and is symmetrical so therefore because of its pole line symmetry it is called polar covalent bond but there are also non polar bonds , this bond can be seen in CH₄ atom where hydrogen bond is not in not in a symmetrical order.

covalent bond in hydrogen

     Ionic Bond

The bond where the magnetic pull of one atom‘s electron is so much that the electron of other atom is directly transferred to the other atom of the first resulting in unequal shearing of electrons. This bond is very strong and electromagnetic energy is evolved in the process with same ionic energy or charges.

Acid, Base and ph value

(Now if someone finds it boring may skip this) Acids are the substance that is the donor of +hydronium ions in a reaction. Some common examples are Hydrochloric acid, Sulphuric acid and many more. Whereas bases are the substances which accept a –hydroxyl ion in a reaction.

 Now let us take simple example

HCL + H₂O THAT IS H₃O⁺ + CL^-

 

 Here HCL is a strong acid which reacts which reacts with water to for 3ioned water of positive charge and chlorine of negative charge.

Now that’s done for chemistry lets go to next topic

Energy and enzymes

The concept of energy is same in every case whether it is chemistry or physics. In cell energy is provided by a combination of certain chemical reaction which is called metabolic process. Reactions carried in cell are of two types Exergonic and Endergonic. The reactions which occur spontaneously are known as exergonic reaction. Whereas the reaction in which certain amount of energy is required to carry out the reaction is called endergonic reaction this reaction can carried out by supply of oxygen or by some other means of energy or fuel.

           The basic power shuttle of cell is adenosine triphosphate (ATP) which is converted to adenosine diphosphate (ADP) an inorganic phosphate. As ATP has more energy than ADP so a huge amount of energy is realized in this conversion cycle

Enzymes

Now when we talk about a series of reaction in cell it must be carried out in order to obtain something useful in product. These reactions are carried out in a sequential manner called as plex series and this series is conducted by a set of special kind of proteins which lower the energy barrier to specify reactions and thereby directing the flow of energy through specific channel. These proteins are called enzymes.

Thank you see more about cell in my next chapter of cell structure and function. We will deal with the nucleus and cell information next time

 

   

  

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My Story on Science and Thrill: Attack of the Garden Ghost

The blood vamp

The most interesting happening was the crowd of vultures which was gathering around the garden and their population was continuously increasing. Soon the older creepy noises started to come from the garden and basement. Basically James was not in favor of this ghost and all the believes, so he started to think more deeply about the whole incident when mother called him "James come down for the dinner you are working too much on your computer come down fast" "but mother I am very busy" said James. "No arguments I want you sitting on the dinning table in two minutes" said mother trying to make her voice hard. Fanny and Richard were already sitting on their (respective) seats for which they usually quarreled and probably get a nice scolding. "Hey brother why are you looking so miserable?" asked Richard. "Well you know the cause of not only mine but all of ours misery that dam ghost. but you know I do not think that it is a real ghost It is some kind of science trick" answered James. "Now what kind of science explains that horrific body and that mist. And not to say those terrible looking vultures" said Fanny pointing towards the horde of birds out side the window. " Oh! maybe chemistry or some kind of new biological experiment" said James in a irritated voice. "Now stop talking about that ghost and eat your dinner" said mother.

         After the dinner all the children went to the bed but James was busy observing the recording and he cried aloud but before he could get to his beloved brother, those vultures started to hit the window glasses flying like bullets toward the house. The mist again started to get thicker and thicker, it rose from the garden area. Till now all the family gathered around the grand sofa kind of trying hide when the books started to fly from the shelf. Mother shouted " Not again the ghost". Suddenly a female body appeared, this body was covered by some red cloth that was flying in the air. Then that strange women showed her face it was like a face carved from meat her eyes were pink and something like slime was coming out of her mouth. She( strangely) spoke " I am the great female vampire the blood vamp while she  killed a vulture which entered the house from the broken window pain. She continued " You foolish people are trying to go against the might of my master the Garden Ghost get your horses out this house. And specially you kid trying to be smart, get out or I will drink your blood and she  (practically) drank the blood of that bird. 

       What was she ? and what was that cry from James? Find out in next chapter ' Two Brothers' 

Alien Anatomy

Alien Anatomy

By Mark Doexy

Howling in pain, The Kraythonian staggered into the surgery clutching upper right arm with upper and lower left hands. Dr Carl Peters slipped on the translator headset. His speech needed to be precise, clear, unrushed. Miss-translation could have unfortunate consequences.

"Hello sir. What appears to be the problem?"

A wall-mounted speaker bellowed grunts and gargles, an interpretation of Dr Peter's words in Kraythonian tongue. The Kraythonian barked and growed a response, distain seeping through pained expression.

A formal, English male voice politely translated in Dr Peters' earpiece.

"Do you have a problem with your eyesight? I'd have thought it obvious that my arm is causing pain."

Kraythonians were known for their forthrightness, not their cheery disposition. They frowned upon rhetorical questions and rarely treated themselves to mirth and merriment, believing levity had no tangible place in the universe. This attitude was matched by their physical appearance, lizard like features and deep red eyes not conducive to warm expression.

Carl took no offence and maintained composure. Differing philosophies and attitudes were all part of working in an inter species environment.

"Of course sir. Please sit on the bed and I'll take a look."

The softness of Carl's tone translated into harsh, even threatening noises from the wall-mounted speaker, totally at odds with the doctor's attempted bedside manner. The Kraythonian language didn't seem to do subtleties. Or maybe they found aggressive growls soothing.

The patient spewed further grunts and gargles as he complied with the doctor's request.

"May I enquire if you're the only doctor on duty today?"

The question didn't surprise Carl. "Yes sir, but I assure you I'm fully trained as regards your physiology."

Another horrific din emanated from the speakers.

Carl had been a medial practitioner on Well's mining facility for several weeks. Well's specialized in mining asteroid belts and was one on the oldest star vessels of it's kind. Much of its equipment was outdated, hence a fairly high accident rate though thankfully nothing serious since his arrival.

The facility was one of the first to introduce an interspecies work environment. Now they were commonplace and believed to improve intergalactic relations. It'd been Carl's father who'd persuaded him to work in such an environment. "See the universe," He'd said. "Meet new and interesting species. Experience cultures from other solar systems." Much of what Carl had learnt thus far was either confusing, scary or down right frustrating.

It didn't help that humans, particularly young, newly arrived humans, weren't well looked upon by the Kraythonian contingent on the mine. And with them making up the majority of those on the station, particularly in positions of authority, this occasionally made matters awkward for the young doctor.

The Kraythonian's viewed Carl, as best any Earth language could translate, as a 'Lower-form'. To have any chance of ascending the social ladder you needed a nomination from a 'Higher-form', which basically meant anyone of a higher social standing. Which basically meant anyone else on the base. Carl had thought being a doctor would put him in better stead, but the Kraythonian's saw the young, fresh faced human rather than his profession.

Curse the Kraythonian's for their beliefs and traditions!

"So, what's your name," asked the doctor?

Names didn't translate, so the earpiece simply repeated the Kraythonian's roar in softer tones. It sounded a little like 'Oomagen'.

"Okay Oomagen, let's see that injury."

The Kraythonian reluctantly allowed Carl to examine the wound. It was a small gash, bleeding not severe but the surrounding inflammation no doubt caused agony. Carl thanked the fact that, whatever the species blood remained blood. It's properties, it's colour and purpose remained the same with only slight deviations. Anatomy varied but blood remained blood.

"So tell me what happened."

Oomagen worked in mineral extraction as an asteroid cutter. A lack of concentration saw him fire a laser cutter while it pointed in the wrong direction. Luckily the cutter had only grazed the arm. Any more and the limb would no longer be there.

Carl delicately prodded the inflammation. "Does this hurt?"

Oomagen pulled away with a howl. No translation needed.

The doctor apologized. "First I have to stop the bleeding."

Carl attempted to place a sterile pad on the wound only for Oomagen to again withdraw, upper and lower left hands protecting the injured limb, lower right grabbing the doctor's wrist. Any contact caused pain. An anaesthetic was needed.

First Dr Peters needed to know a little about Oomagen's medical history. He fetched his handheld scanner from a nearby desk. "Have you been in mineral extraction long?"

The Kraythonian claimed to have been in the post for twelve years. Carl thought it unusual that an employee so experienced would make such an error with a laser cutter, especially considering the species' reputation for methodical professionalism.

Carl zapped the bar code on Oomagen's ID badge with the handheld. The employee had no history of allergies and was not currently on any medication. This aided Dr Peters in selecting an aesthetic.

Haloprodian D6. A toxin that ignited pleasure sensors in the brain, thus giving the patient a serine, benign feeling and shutting out pain receptors from elsewhere in the body. Get the dosage right and the Kraythoian would let Carl do whatever he wanted with the injured arm. He loaded a syringe.

The doctor asked the usual formal questions before administering. "Have you been feeling ill or faint recently, or consumed anything intoxicating in large quantities?" He fished for an explanation for the Kraythonian's uncharacteristic mishap.

Oomagen grew impatient.

"No. Are you going to help me or will the silly questions persist?"

Satisfied he had the correct dosage, Carl reassured his patient. "Of course sir. First a little something to take away the pain."

The Haloprodian D6 was injected into Oomagen's upper right arm. It would take only several seconds for the drug to tale effect.

The Kraythonian remained sceptical.

"Are you sure there isn't another doctor around who can..."

Oomagen's growling ceased. Mouth open, Carl's patient suddenly swayed, red of his eyes going dull as they stared into space.

Carl eased the Kraythonian into a reclining position on the bed. "Now just relax sir, we'll have that wound sorted out in no time."

Oomagen responded, his growl now a purr. The purr translated as "Thank you."

"You're welcome."

Carl set to work dressing the wound, Oomagen content to lie and watch, mesmerised by the doctor's actions.

The doctor felt he deserved a drink for the way he'd maintained professionalism in the face of such an abrasive patient. Unfortunately such reward would have to be consumed in the privacy of his own cramped quarters. 'Lower-forms' weren't allowed in the mine's bar, or 'Meeting place' as the Kraythonians imaginatively referred to it. That's where they gathered for their rare moments of frivolity. Kraythonians didn't entirely disapprove of fun, just so long as they indulged in the right location at an appropriate time. 'The Meeting Place' provided that location. A place to enjoy brief moments of frivolity before returning to the serious business of real life.

Oomagen purred.

"Sorry for being nasty earlier. I like humans really you know."

The comment surprised and amused the doctor. "Why thank you very much."

The Kraythonian's lower right hand started to gently stroke Carl's leg.

"To be honest I think you're all really cute."

Now Doctor Peters felt uncomfortable. It was always possible that verbal exchanges could be misinterpreted, physical contact less so. Was this just something harmless Kraythonians did to those who helped them, maybe part of the culture? Or were there more amorous intentions afoot? Carl removed Oomagen's hand from its questionable activity and turned to move away.

"Well that's very nice of you to say so but..."

Oomagen pulled Carl back, sat up and embraced him.

"Oh give me a hug."

Carl didn't feel so much hugged as crushed, the Kraytonian still incredibly strong despite the sedative. Eventually he managed to free himself and gently recline the patient back onto the bed. "Thank you very much but you must rest for a few moments. I just need to run a test."

"Is it okay if I sing?"

An unusual request but Carl saw no harm in the activity. "Of course, just don't be too loud."

As the doctor fetched a blood test kit Oomagen broke into an elongated, tuneful growl and purr, the translator spinning a tale of undying love in broken English. Oomagen's behaviour could simply be down to the Haloprodian D6 but Carl had never seen such an extreme reaction. Also, the administered dose should have sapped the patient of strength, something that on this occasion had most definitely not been the case. Something was wrong!

"I just need a sample. You'll feel a little prick." For a second Carl feared his second statement would be translated as something embarrassingly different.

Oomagen briefly broke from singing.

"Do what you must my friend."

Dr Peters inserted the needle and took the sample.

Oomagen laughed.

"It tickles."

Singing resumed, the translator recalling the location at which first true love had been experienced.

Carl placed the blood into a handheld monitor and waited for the results. When they arrived the doctor felt his jaw drop.

Oomagen was pregnant!

* * *

Dr Carl Peters drank his ale; laughing with friends in a bar he wasn't welcome in several weeks earlier. Oomagen was among them, naturally careful of substances consumed in current condition.

Carl had been right. Oomagen was indeed pregnant. Kraythonian tradition dictated that a person who discovers the condition and breaks the happy news is owed a debt by the expecting. Once the effects of the Haloprodian D6 had worn off an overjoyed Oomagen was only too happy to grant any wish within her power. Carl asked to be nominated to step up the social ladder. Oomagen gladly complied.

Elevation to a 'Higher-form' gave other employees reason to be more open to socialising with the doctor and friendships were quickly established. Respect was even growing; Carl now viewed not as an inferior but as a Doctor. A noble professional.

Someone in authority, another of his new friends, even saw to it that the good doctor received a pay rise and was moved to better, more spacious accommodation.

My, how Carl loved Kraythonian tradition.

Bio: Mark Doxey is a young at heart dreamer who loves telling stories

My Story on Science and Thrill- Attack of The Garden Ghost

Part One- Chapter 2

Not Again (The blood vamp)

After some time the siren, bell rang many police cars came up just missing to hit each other. Richard and inspector Mackal came out from the first big car with the biggest bumper. The Inspector was a big man dressed in blue with a big mustache and brown hair. When father saw Richard with him in half consciousness, he stood up and called Richard,"My son where were you and is that a cop.." "Just relax father this is inspector Mackal of nearby station, but where is mother, is she alright."said Richard. "Oh no I also forgot about here she was somewhere near the couch,"said father. When Richard looked around he saw here on the ground lying unconscious near the grand sofa. He called the medics for first aid treatment. When medics examined the mother they said that she looks like to be drugged but their are no specific symptoms of any kind of drug. After some time Mackal asked father" Sir can you explain that what exactly happened here" "Yes of course I can. Around three hours from now me and my wife were working on our budget when a horrific ghost appeared and then we were just knocked out" said father. "Is this joke or what ? please sir do not say that you have called us for this purpose." said inspector. Well, the day passed on but no one was able to believe in fathers story.Time passed very calmly but one night their was smell of blood lust in the air again birds flew to the sky, vultures gathered around the the house after all what was happening around. (The ghost is returning!)  

 

Cell Structure and Function: Part Two

Cell structure and function

1. Nucleolus
2. Nucleus
3. Ribosomes
4. Vesicle
5. Rough endoplasmic reticulum(ER)
6. Golgi apparatus
7. Cytoskeleton
8. Smooth(ER)
9. Mitochondrion
10. Vacoule
11. Cytosol
12. Lysosome
13. Cetrosome
14. Cell membrane 

Nucleus

Nucleus is a membrane organelle found in eukaryotic cells. It is the main functioning body of the cell. The nuclear material in prokaryotic cells is not enclosed with in membrane to form nucleus which shows the underdeveloped cell structure. Nucleus as I described has three main parts Nuclear membrane, Nucleoplasm and Nucleolus. To get information about these I insist you to read the first part. As we know that nucleus contains the genetic coding in form of  DNA molecules bind together to form chromosomes by proteins such as Histones.

Ribosomes

Ribosomes are complex molecular bodies which are found in all living cells and are basic bodies responsible for protein synthesis as directed by messenger RNA or mRNA. These structures are produced by nucleolus and are conducted by rough ER into the the cytoplasm. As ribosomes are made up of complex RNAs so they are called ribonucleoprotein. Each ribosome is divided into two subunits: a smaller subunit which binds to the mRNA pattern, and a larger subunit which binds to the tRNA and the amino acids. When a ribosome finishes reading an mRNA molecule, these two subunits split apart. Ribosomes are ribozymes, because the catalytic peptidyl transferase activity that links amino acids together is performed by the ribosomal RNA.

BLUE (SMALLER UNITS)

Mitochondrion

The mitochondrion (plural mitochondria) is a membrane-bound organelle found in most eukaryotic cells 
Mitochondria range from 0.5 to 1.0 micrometer in diameter. These structures are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in other tasks such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several human diseases, including mitochondrial disorders and cardiac dysfunction, and may play a role in the aging process. More recent research indicates that autism, especially severe autism, is correlated with mitochondrial defects.

Rough ER

The endoplasmic reticulum (ER) is a type of organelle in the cells of eukaryotic organisms that forms an interconnected network of flattened, membrane-enclosed sacs or tubes known as cisternae. The membranes of the ER are continuous with the outer membrane of the nuclear envelope. Endoplasmic reticulum occurs in most types of eukaryotic cells, including the most primitive Giardia, but is absent from red blood cells and spermatozoa. There are two types of endoplasmic reticulum, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). The outer (cytosolic) face of the rough endoplasmic reticulum is studded with ribosomes that are the sites of protein synthesis. The rough endoplasmic reticulum is especially prominent in cells such as hepatocytes where active protein synthesis occurs. The smooth endoplasmic reticulum lacks ribosomes and functions in lipid metabolism, carbohydrate metabolism, and detoxification^{[citation needed]} and is especially abundant in mammalian liver and gonad cells. The lacey membranes of the endoplasmic reticulum were first seen in 1945 by Keith R. Porter, Albert Claude, Brody Meskers and Ernest F. Fullam, using electron microscopy.

Lysosomes

Lysosome is a membrane-bound cell organelle found in animal cells (they are absent in red blood cells). They are structurally and chemically spherical vesicles containing hydrolitic enzymes, which are capable of breaking down virtually all kinds of biomolecules, including proteins, nucleic acids, carbohydrates, lipids, and cellular debris. They are known to contain more than fifty different enzymes which are all active at an acidic environment of about pH 5. Thus they act as waste disposal system of the cell by digesting unwanted materials in the cytoplasm, both from outside of the cell and obsolete components inside the cell. For this function they are popularly referred to as "suicide bags" or "suicide sacs" of the cell. Further, lysosomes are responsible for cellular homeostasis for their involvements in secretion, plasma membrane repair, cell signalling and energy metabolism, which are related to health and diseases.^[1] Depending on their functional activity their sizes can be very different, as the biggest ones can be more than 10 times bigger than the smallest ones. They were discovered and named by Belgian biologist Christian de Duve, who eventually received the Nobel Prize in Physiology or Medicine in 1974. 

 

SOME MORE ORGANELLES IN NEXT POST

 

Cell Structure and Function : Part One

Cell Introduction

Cell is the basic structural and functional unit of life. Every function of body is carried out by  cell. The unit cell was first observed by Robert Hooke in 1665 when he was studying a cork and he saw very small units resembling the compartments of honey bee comb. The study of cell structure and function is called cytology. On the basic field of distribution cell is broadly categorized into three parts-

1. Cell membrane
2. Cytoplasm
3. Nucleus

Cell membrane- Cell membrane is thin layer outside the cell also known as plasma membrane or cytoplasmic membrane. Its main function is to diffuse the organic molecule and synthesise protein and carry out exocytosis and endocytosis to gain and food and excrete bad material.

Cytoplasm is derived from two words Kytos and plasma which means hollow thick liquid. It is composed of various organic molecules and bear the load of all the organelles. It is made up of  various protein and glucose molecules. this fluid is a dense form of living body and also transports the organic food for metabolism.

 When we talk about nucleus it is the main functioning body of cell. It is further made up of three parts namely Nuclear membrane which is like the cell membrane and carries out almost same functions like the cell membrane. It separates the nuclear material by other organelles of the cell. The second part of nucleus is the nucleoplasm which contains the chromatin material. And at the last comes the nucleolus which is the core of the nuclear body and contains precise genetic programming for hereditary in off spring.   

Read intro here