Outline the functions of the main cell organelles
The main cell organelles are –
This cell organelle releases energy for the cells. It is known as the power house of the cell. This organelle acts like a digestive system this is because it takes nutrients in, breaks them down and creates energy for the cell. The process of doing that is referred to as Cellular Respiration. Most of the chemical reactions involved in this process happen in the Mitochondria. If the cell feels as though it is not getting enough energy to survive then it can create more Mitochondria. They are also able to grow more Mitochondria and combine with other Mitochondria depending on what the cell needs. Mitochondria are oblong shaped and can be found in the cytoplasm of every eukaryotic cell. In an animal cell they are known as the main power generators in this case they convert oxygen and nutrients into energy.
The function of this cell organelle is known as the packaging system. It is a network of sacs that manufactures, processes, and transports chemical compounds for use inside and outside of the cell organelle. It is connected to the double-layered nuclear envelope, providing a connection between the nucleus and the cytoplasm. This cell organelle works very closely with the Golgi Appartus and Ribosomes. It creates a network of membranes that are found through the whole of the cell. Although there are two types of Endoplasmic Reticulum, Rough and Smooth, they both work the same way although have different shapes to each other.
Rough Endoplasmic Reticulum
The rough Endoplasmic Reticulum has Ribosomes attached to it. It looks like sheets of bumpy membranes. These are important in the synthesis and packadging of proteins. Some may be used in the cell and some sent out. The function of Rough endoplasmic reticulum is to perform the synthesis of proteins and transport of many biochemical compounds in a cell.
Smooth Endoplasmic Reticulum
This type acts as a storage organelle this is because it stores ions. It is important in the creation of steriods. It function is the same as the rough endoplasmic reticulum.
This organelle is found in most cells. It is a packaging organelle. The Golgi Appartus gathers simple molecules and combines them to make molecules that are more complex. It then takes the big molecules and packages them into vesicles and either stores them to use later or sends them out of the cell. The Golgi apparatus is the distribution and shipping department for the cell’s chemical products. It modifies proteins and fats built in the endoplasmic reticulum and prepares them for export to the outside of the cell. The vesicles are pinched off the membranes and float through the cell.
The main purpose of the Lysosomes is to digest things. The Lysosomes hold enzymes that were created by the cell. Lysosomes maybe used to digest food or break down the cell when it dies. Lysosomes break down cellular waste products and debris from outside the cell into simple compounds, which are transferred to the cytoplasm as new cell-building materials. It is a specialised vesicle that holds a variety of enzymes. These enzymes are first created by the rough Endoplasmic Reticulum. They are then packaged into a vesicle and sent to the Golgi appartus. The Golgi Appatus then creates the digestive enzymes and pinches off a smooth, very specific vesicle (lysosomes) they then float around the cytoplasm until they are needed. Nucleus
The Nucleus acts like the brain of the cell. It helps control eating, movement and reproduction. The Nucleus is not always found in the centre of the cell. The Nucleus appears to be a big dark spot somewhere in the middle of all cytoplasm.The Nucleus is a highly specialized organelle that serves as the information and administrative center of the cell.
Outline The Structure Of The Four Main Tissues –
Outline the structure of the four main tissues of the body these are Epithelial, Connective, Nervous and Muscular. Name and describe the cells that make up the tissue and describe the function of the tissue. There are four types of tissues
The Epithelial tissue is the lining of internal and external surfaces and body cavities, this includes ducts. The Epithelial tissues can be composed of several layers of cells, these are referred to as compound Epithelial. They can also be compound of a single layer of cells and called simple Epithelial. The lowest or bottom layer of cells is attached to a basement membrane for support and connection. The function of the Epithelial is to protect the underlying structures, secretion and absorption. Simple types of Epithelial tissues-
They may be
Squamous – Scaley
This type of cell is very flat. Each nucleus forms a lump in the centre. They
fit closely together and are delicate thin cells that offer little protection. Their primary function is to allow materials to pass through by diffusion and osmosis. Simple Squamous Epithelial cells are found in the wall of; lung alveoli, blood capillaries and bowman’s capsules of nephrons.
Cuboidal – Cube Shaped
The simple Cuboidal Epithelial allows materials to pass through in a similar way to the Squamous Epithelial. They line the ducts, tubes and occur in glandular tissues, making secretions. They can be found in; kidney tubules, sweat ducts and glands like thyroid glands. They also occur in glandular tissues making secretions.
The simple Columnar is a slightly oval nuclei. Its associated with microscopic filaments, these are called Cilia. Cilia move in wave like motions. Simple columnar epithelial cells are some of the most prolific cells in the body, mainly because they can fulfill so many functions. They are found throughout the body’s organ system, including the digestive tract and the female reproductive system. They are found in the respiratory system, including the nasal passage. Simple columnar epithelial cells are longer than they are wide. Characteristically, their nucleui are found at the base of the cell. The cells are connected by tight junctions. The cells receive nutrients through the basement membrane, which separates the cells from the capillary basal layer.
Ciliated Epithlium lines the outermost and innermost surfaces of the body. It is named for the presence of cilia, or thin, finger-like hairs, on its surface. These cilia move in one direction in a wavelike pattern, allowing the cells to sweep away debris, direct the flow of particles, and create a current. This type of epithelium can be found in the body’s air passages, including the lungs, trachea, and nose; in the fallopian tubes and uterus; and in the brain. In the airways, ciliated epithelium is necessary to keep dust and debris out of the lungs, because it controls the flow of mucus. Particles in the air are trapped by the mucus in these passageways, and the
sweeping motions of the cilia direct the mucus away from the lungs and out of the body. In the fallopian tubes, cilia sweep an ovum down toward the uterus, where uterine cilia position it or sweep it out of the body. This tissue helps circulate cerebral fluids in the ventricles of the brain. Connective Tissues
These are the most widely distributed tissues in the body. They lay beneath the Epithelial tissues connecting different parts of the internal structure. Various cells lie in a background material known as the matrix. The matrix may be liquid as in blood, jelly- like as in areolar tissue, firm as in cartilage, or hard as in bone. The matrix of a tissue is normally secreted by the connective tissue cells. The main function of the connective tissues is to transport materials ie: blood, give support to the areolar tissue and cartilage and strengthen and protect bones. You can find connective tissues in blood, cartilage, bone, areolar tissue and fatty tissue.
There are three different types of muscle in the human body, Straited, non-straited and cardiac. Muscle tissue is capable of responding to stimuli. Each different muscle type is composed of muscle fibres that are capable of shortening and returning to their original state, known as relaxation. The contraction causes movement of the skeleton, soft tissues, blood or specific material such as urine, food and faeces. It has both nerve and blood supply.The muscle of the arteries contracts and relaxes to regulate the blood pressure and the flow of blood. striated muscle is attached to the bones of the skeleton, although some facial muscles are attached to the skin. The muscle contracts when it receives nerve impulses controlled by the conscious thought from the central nervous system. Muscles can be divided into three main groups according to their structure, e.g.: Smooth muscle tissue.
Skeletal muscle tissue.
Cardiac (heart) muscle tissue.
Nervous tissue allows an organism to sense stimuli in both the internal and external environment. The stimuli are analysed and integrated to provide appropriate, co-ordinated responses in various organs. The sensory neurons conduct nerve impulses from the sense organs and receptors to the central nervous system. Connector neurons supply the connection between the afferent and efferent neurons as well as different parts of the central nervous system. Efferent or somatic motor neurons transmit the impulse from the central nervous system to a muscle which then react to the initial stimulus. Autonomic motor or efferent neurons transmit impulses to the involuntary muscles and glands. Nervous tissue is specialised to react to stimuli and to conduct impulses to various organs in the body which bring about a response to the stimulus. Nerve tissue (as in the brain, spinal cord and peripheral nerves that branch throughout the body) are all made up of specialised nerve cells called neurons. Neurons are easily stimulated and transmit impulses very rapidly. A nerve is made up of many nerve cell fibres (neurons) bound together by connective tissue.
The Main Body Systems
Outline the gross structures and the functions of all the main body systems Renal
Body systems – Reproductive, Lympatic, musculo-skeletal, immune
Renal System- The renal system consists of two kidneys, they have emerging tubes known as the ureters running down to the bladder. The passage from the bladder to the exterior is through the Urethra. The passage of urine is controlled by the sphincter muscle. Kidneys are supplied by short renal arteries, coming out of the main artery of the body, known as the Aorta. Renal veins take the blood from the kidneys straight into the vena cava, this is the main vein of the body. Its main function is to make sure that
our bodily fluids are within normal limits, it also makes sure that are blood stays at the correct pH. The renal systems is located in the upper area of the abodomen.
The nervous system consists of the brain, spinal cord and many complex neurons. This body system is important in the feeling pain and pleasure. It sends signals to our brain to tell us whether something hurts us or not, for example, when we burn our hand on something hot our nervous system tells us that this is painful and therefore causes us to have a natural reaction to pull back from the hot object. It does this by sending a signal to our brain to warn us. The nervous system is responsible for sending, receiving and interpreting information from all over your body. Your nervous system monitors and co-ordinates internal organ function and responds to changes in the external environmental. The nervous system can be divided into two parts, the central nervous system and the peripheral nervous system. The central nervous system sends and receives information to your peripheral nervous system. The two main organs of the nervous system are the brain and spinal cord. The brain reads, processes and interprets information that is sent from your spinal cord. Therefore the main function of your nervous system is to send and receive signals.
The Endocrine System-
This is a collection of ductless glands that are scattered throughout your body. The endocrine glands pass their secretions otherwise known as hormones directly into the bloodstream so that they are always next to the blood vessels. The endocrine system is responsible for things such as cell growth and any other body processes that happen slowly.The endocrine system is responsible for regulating mood, growth and development, tissue function, metabolism, sexual function and reproductive processes. The foundation of the endocrine system are mainly hormones and glands. The major glands that make up the human endocrine system include the: hypothalamus
The Reproductive system-
The function of the reproductive system is to reproduce and create new life. It does this by either producing egg or sperm cells, it then transports and sustains these cells, to nurture the developing offspring, and to also produce hormones. The major organs of the reproductive system include the external genitalia and internal organs, including gonads that produce gamete, which is a cell that fuses with another cell during conception in organisms that reproduce sexually. Substances such as fluids, hormones, and pheromones are also important to the effective functioning of the reproductive system. Males and females have different reproductive organs, these serve different purposes.
The Lympatic System-
There are hundreds of lymph nodes all over the body. The lymph nodes often associate in groups. Lymphoid tissues also occur in specialised areas, more associated with potential sources of infection, these include tonsils adenoids, small intestines, spleen and thymus gland. It defends the body against infectons and helps keep bodily fluid levels in balance. The lymphatic system is made up of a network of lymphatic vessels. These vessels carry lymph this is a clear, watery fluid containing protein molecules, salts, glucose, urea, and other substances , throughout the body. One of the main jobs the lympatic system has to do is to collect extra lymph fluid from the bodys tissues and return it to the blood. This is important because water, proteins, and other substances leak out of small blood capillaries into the body tissues and if the lymphatic system didn’t drain the excess fluid from the tissues, the lymph fluid would build up in the body’s tissues and they would swell up. The lymphatic system also helps defend the body against germs like viruses, bacteria, and fungi that can cause illnesses. Those germs are filtered out in the lymph nodes, which are small masses of
tissue located along the network of lymph vessels.
The Musculo-skeletal system-
This system is made up of bones, muscles, ligaments and tendons. The function of the musculoskeletal system is to:
protect and support the internal structures and organs of the body allow movement
give shape to the body
produce blood cells
store calcium and phosphorus
The immune system-
The immune system is more scattered than other systems. It is a collection of cells, tissues and proteins that protects the body from invasion from harmful micro-organisms. The immune system, is made up of cells, proteins, tissues, and organs, defends people against germs and microorganisms every single day. In most cases, the immune system keeps us healthy by preventing infections . But sometimes problems with the immune system can lead to illness and infection, this may be because we have something like a simple like a cold which makes are Immune system weak and then leads up to catching a more significant illness.
The heart is a muscular pump that forces blood around the body through a system of blood vessels, arteries, veins and capillaries. Blood carries dissolved oxygen to the body cells and at the same time removes the waste products of respiration (carbon dioxide and water). Blood is also important in distrubuting heat around the body, along with hormones, nutrients, salts, enzymes and urea. The cardio-vascular system protects, transports and regulates.It protects the body through white blood cells, The cardiovascular system transports blood to almost all of the body’s tissues. The blood delivers essential nutrients and oxygen and removes wastes and carbon dioxide to be processed or removed from the body.
Respiration can be divided into external respiration, compromising of breathing, gaseous exchange and blood transport and internal or tissue respiration, which is carried out inside body cells. Everyday we breath around 20,000 times.The respiratory system includes the nose, throat, voice box, windpipe, and lungs. We are able to breath through either our mouth or nose. The function of the respiratory system is to get oxygen to the blood, lungs and your body as a whole, but to also remove carbon dioxide from your body.
The main function of your digestive system is to digest food, break it down and turn it into energy that your body can use. When we eat food, we use our teeth to break it up so that it is easier for us to swallow, the saliva in our mouth makes this an easier process. The process Is called mechanical digestion and is an important part of physically breaking the food down at an early stage. The system also relies on the pancreas, liver, and gall bladder to help digest food .
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