Cell membrane- holds all thecell pieces and fluids inside the cell and keeps other things out.Nucleus- contains thegenetic material.

Cytoplasm- the materialwithin the cell, this is excluding the nucleus.Mitochondria- It is like adigestive system that takes nutrients, breaks them down and creates moleculeswhich are rich in energy for the cell. It is also popularly known as thepowerhouse of the cell.

Endoplasmic reticulum- worksas the manufacturing and packaging system.Smooth ER-  acts as a storage organelle.Rough ER- synthesizesproteins. Called the rough ER because it has ribosomes attached to the surface.

Golgi apparatus- It isanother packaging organelle like the ER. It gathers simple molecules andcombines them to make more complex molecules. It then takes them, stores themfor later or sends them out of the cell or packs them in vesicles.Lysosome- A single membraneorganelle that holds a variety of enzymes. The enzyme proteins are first madein the ER and packaged in a vesicle and sent to the Golgi apparatus where thefinal work is done and then it is a lysosome and is kept in the cytoplasm untilit is needed.   Outline the structure of themain tissues of the body.Epithelial Tissue Epithelial tissue- itprotects and covers and it is a reproductive tissue. Protects the body fromdirt, dust and bacteria etc.

It can come in a variety of shapes but the cell isusually thin, flat and elongated. Colour of epithelial tissue is pink. Theepithelial cells are very closely packed together and dense.Different types ofepithelial tissue: Epithelial tissue can be either simple or compound.

Thedifference between the two is. Simple epithelium consists of a single layer ofliving cells whereas compound epithelium consists of a few layers of living andnon-living cells. Simple does mainly secretory and absorptive functions andcompound performs the protective function. Lastly, for the simple epitheliumall the cells are set on basement membrane but with the compound epithelium thecells are set on the deepest layer of the basement The different types ofsimple epithelium:Simple squamous epitheliumThis type of epithelium tissue is found in the lining ofthe heart, air sacs of the lungs, lymphatic vessels and blood vessels. Thefunction of the squamous epithelium is to allow different types of materials topass through by diffusion and filtration.Simple cuboidal epitheliumThis type of epithelium is found in hidden portions ofsmall glands, kidney tubules and the ducts. It is found in organs thatspecialise in secretion like the ones I have named. The tissue consists of asingle layer of cuboidal cells on the basement membrane.

Simple columnar epitheliumIt is found in the ciliated tissues including thebronchi, uterine tubes, uterus; smooth non-ciliated tissues are in thedigestive tract bladder. The function of this tissue is to absorb and secretethe enzymes and mucous.  Simple ciliatedepitheliumThis occurs inmany places, including the brain, digestive system and reproductive tract. Thisis a body tissue that is lined with cells that are like small hairs which caneither help the cells move along tissue or can help move waste along thesurface of the cells.  Differenttypes of compound epithelium:Simple compoundepithelium: This is made upof multiple layers of cells and has a limited role in secretion and absorption.

The main function of the compound epithelium is to protect against chemical andmechanical stresses.      Keratinizedcompound epithelium:The cells on thesurface of the keratinized epithelium are very flat. The cells are also nolonger alive and are cemented together to create thick skin. They have nonucleus or organelles. They are filled with a protein called keratin whichmakes our skin water proof and protects it from damage or stress. ConnectivetissueThe connective tissue istissue that connects, supports, binds or separates other tissue or organs.Unlike the epithelial tissue which has cells that are closely packed together,connective tissue normally has cells scattered throughout an extracellularmatrix of fibrous proteins and glycoproteins attached to a basement membrane.

Different types ofconnective tissue:   BloodAlthough there is a separatefunction for blood, It is also a connective tissue as it has an extracellularmatrix. The matrix contains the plasma. Whilst the red blood cells, white bloodcells and the platelets are suspended in the plasma.Cartilage: This is a firm tissue thatis much more soft and flexible than the bone.

It is found in the joints betweenthe bones such as elbows and knees. BoneThis is a firm, solidconnective tissue that has a large amount of 2 matrix material which iscollagen and elastic fibres. AdiposeThis is a form of loose connective tissue that stores fat. It linesorgans and body cavities to protect organs and protects the body against heatloss and produces endocrine hormones which is a system that is made up of anetwork of glands which secretes hormones to regulate many bodily functionslike growth and metabolism.

AreolarThis is found in surrounding blood vessels, nerve bundles, muscles andorgans. It attaches epithelium to underlying tissues and allows diffusion ofnutrients to epithelial cells. Muscle Tissue Muscle tissue is a collection of cells that bond in order to producemovement of the body parts. This tissue is well supplied with blood vessels. Themuscles are dense tissues which primary function is to allow the body to moveby repeated contraction.

Besides movement, the muscle is also responsible formaintaining posture, stabilizing the joints and producing body heat throughmuscle function. Striated muscleThis muscle tissue is mainly attached to the bones and skin and isresponsible for the mobility of the body and limbs. Striated means striped, sothe muscle is striped.Non-striated muscleThis muscle is also known as the smooth muscle. This muscle forms organslike the stomach and bladder and it changes shape to facilitate bodilyfunctions. Cardiac muscleThis is a tissue that has evolved to pump blood throughout the body.

Thecardiac muscle is only found in the heart and makes up the bulk of the heartsmass. Nervous tissueNervous tissue is found in the brain, spinal cord and nerves. It isresponsible for controlling many body activities.

It stimulates musclecontraction, makes you aware of your surroundings and plays a major role inyour memory, your emotions and your reasoning. Nervous tissue is the tissue thatmakes the central nervous system and the peripheral nervous system. Nervous neuron tissueNeurones are responsible for sensing stimuli and transmitting signals toand from different parts of an organism. The structure of a neuron is uniquelysuited to its function within nervous tissue. A neuron consists of two major parts:Cell body: this contains the neurons nucleus which isassociated with cytoplasm and other organelles.

Nerve processes: these are able to conduct and transmit signalsfrom the cell body. There are wo types of these. Axons- carries signals awayfrom the cell. Dendrites- carries signals towards the cell body.

     Nervous Neuroglia tissueThese cells that form myelin,protect, support and maintain equilibrium in your nervous system. They arecalled glial cells. They compose a big support system that is essential to theproper operation of nervous tissue and the nervous system. An outline of the grossstructure of the main body systems listed below:Cardiovascular system The cardiovascular system is also known as thecirculatory system which contains the heart, the blood vessels and the blooditself as its 3 components. The circulatory system consists of two circuitsthat blood travels through; pulmonary circuit and systemic circuit. The pulmonary circuitcarries blood to the lungs to be oxygenated andthen back to the heart. In the lungs, carbon dioxide is removed from the blood,and oxygen taken up by the haemoglobin in the red blood cells.

The systemic circuitcarries blood around the body to deliver the oxygen and returns de-oxygenated blood to the heart.Blood also carries nutrients and waste.Exercise affects these systems, causing the heart to pumpblood faster around the body, which in turn allows you to exercise for longer. It is a double circulatory system. It comprises twoseparate circuits and blood passes through the heart twice.       Therespiratory systemConsisting of specific respiratory organs, blood vessels and muscles,the respiratory system is responsible for inhaling oxygen and carrying out theexchange of oxygen and carbon dioxide in the human body.

 Main functions of the respiratory system:Inhaling and exhalingExchange of oxygen and carbon dioxide between the lungs and bloodstreamExchange of oxygen and carbon dioxide between the bloodstream andtissuesCreating vibration of the vocal cords to produce soundHelping with the sense of smell The human respiratory system has several main parts. Thetable summarises these and lists their functions. Part Function Trachea The windpipe – it leads from the nose and mouth to the two bronchi Bronchus Tube leading from the trachea to a lung Lungs Contain the gas exchange surfaces Bronchiole Smaller tubes inside the lungs leading from the bronchus to the alveoli Alveoli Tiny air sacs at the end of bronchioles, where gas exchange happens Pleural membranes Allow the lungs to move easily during ventilation Ribs Provide a moveable cage to enclose and protect the lungs Intercostal muscles Allow the ribcage to change in volume for ventilation to happen Diaphragm Works with the intercostal muscles to allow ventilation to happen  Digestive system Digestion is the breakdown of large molecules intosmaller, soluble molecules that can be absorbed into the body.

Digestionhappens inside the gut, and relies on enzymes. It is a group of organs workingtogether to convert food into energy and the basic nutrients to feed the entirebody.  Renal systemThis system consists of the kidneys, ureters, urinarybladder and urethra. The kidneys are a pair of bean-shaped organs found alongthe wall of the abdominal cavity.

The kidneys are surrounded by a layer ofadipose that holds them in place and protects them from damage. The kidneysfilter metabolic wastes, excess ions, and chemicals from the blood to formurine. The ureters, urinary bladder and urethra together from the urinarytracts all act as a plumbing system and drain the urine from the kidneys tostore it and then release it during urination. As well as filtering andeliminating wastes from the body, the renal system also maintains thehomeostasis of water, ions, Ph, blood pressure etc.           Nervous system The nervous system consists of the brain, spinal cord,sensory organs, and all the nerves that connect these organs with the rest ofthe body.

Together, these organs are responsible for the way the body iscontrolled and the communication amongst its parts. The spinal cord and brainform the control centre which is known as the central nervous system (CNS).This is where information is evaluated and decisions are made. The sensorynerves and sense organs of the peripheral nervous system (PNS) monitor conditionsIn and outside of the body and send this info to the CNS. Efferent nerves inthe PNS carry signals from the control centre to the muscles, glands, andorgans to regulate their functions.    Endocrine systemThe endocrine system is the collection of glands thatproduce hormones that regulate metabolism, growth and development tissuefunction, sexual function, reproduction, sleep, and mood.

This system is madeup of the pituitary gland, thyroid gland, parathyroid glands, adrenal glands,pancreas, ovaries (in females) and testicles (in males), the mayo clinic notes. Reproductive system The reproductive system is a collection of internal andexternal organs, which are in both males and females. They work together forthe purpose of procreating. The male reproductive system consists of 2major parts. Thetestes, which is where the sperm are produced. The testes are carried in anexternal pouch known as the scrotum which is where they remain slightly coolerthan body temperature to enable sperm production.

       The female reproductive system includes the clitoris,labia, minora, labia majora and the Bartholin’s glands. The major internal ofthe female reproductive system include the vagina and uterus which acts as thereceptacle for semen- and the ovaries, which produce the female’s ova. Thevagina is attached to the uterus through the cervix, while the fallopian tubesconnect the uterus to the ovaries. In response to hormonal changed, one egg-ormore in the case of multiple births- is released and sent down the fallopiantube during ovulation.

If not fertilized, this egg is eliminated because ofmenstruation.  Lymphatic system This system is a network of tissues and organs that helpthe body to get rid of toxins, waste and other unwanted materials. The functionof the lymphatic system is to transport lymph- which is a fluid containinginfection-fighting white blood cells, throughout the body. The lymphatic systemconsists of lymphatic vessels.

The vessels are connected to lymph nodes- whichis where the lymph is filtered. The tonsils, adenoids, spleen and thymus areall part of the lymphatic system.   Musculo-skeletal system This system provides stability and movement to the humanbody.

It consists of the body’s bones, muscles, tendons, ligaments, joins,cartilage and other connective tissue. In addition to movement, musclecontraction also helps with other important function’s in the body such asposture, joint stability and heat production- nearly 85% of the heat producedin the body is the result of muscle contraction.  Immune system This system is a network of cells, tissues and organsthat work together to defend the body against attacks. These are primarilymicrobes- tiny organisms such as bacteria, parasites, and fungi that can causeinfections. The human body provides an ideal environment for many microbes.

Itis the immune systems job to keep them out or to destroy them. When the immunesystem hits the wrong target, however, it can unleash a torrent of disorders,including allergic diseases, arthritis, and a form of diabetes. If the immunesystem is crippled, other kinds of diseases result. The immune system is made upof all the body’s organs.

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