Keratinised:
This type of tissue is found on dry surfaces which are likely to ear and tear such as the skin, hair and nails. The surface layer that covers this tissue is made of dead epithelial cells which consist of the protein keratin. This produces a hard and waterproof layer which protects and prevents the cells underneath from drying.
Connective:
Connective tissues lie under the epithelial tissues and connect the different body parts. The matrix of the tissue is usually secreted by the connective tissue cells. Its functions are to give support, transport materials and also to strengthen and protect. To provide special characteristics some tissues contain different fibres which are secreted by the cells.
Blood:
Blood is a connective tissue. It’s what carries information through the cells to various parts of the body and external environment. Transportation of substances is the main function of the blood. The blood is used to transport:
- Oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs
- Nutrients to the tissues and cell wastes to organs such as the kidneys so that they can be excreted
- Hormones to the required body organs
- Heat that is formed in active tissues is transported through the blood to less active tissues.
- Antibodies to areas of the body that are infected
The blood is made up of a clear fluid called plasma. The blood is made up of about 55% of plasma fluid and about 45% of blood volume. The plasma is made up of water and substances such as plasma proteins, inorganic salts, nutrients, waste substances, hormones and gases.
Plasma, red blood cells and white blood such as lymphocyte, neutrophil and eosinophil are all part of the blood.
The bone:
The bone is made up of bone cells that sit in a type of cavity called the lacunae and is surrounded by layers of matrix that consist of calcium salts and a large amount of collagen fibres. The fact that the bone is hard gives it the responsibility of protecting other organs. For example the skull protects the brain and the rib cage protects the heart, lungs and kidneys.
Cartilage:
Cartilage is softer and more flexible compared to the bone. Cartilage is found in very few places within the human body. The hyaline cartilage is the most widespread cartilage, it contains collagen fibre which are covered with rubbery matrix. The hyaline cartilage forms structures that support the voice box and also structures that attach the ribs to the breast bone, which covers the ends of the bones and then joints, are formed.
The hyaline cartilage is not the only cartilage that is found in the body, other cartilages in the human body include fibro cartilage and the elastic cartilage. Discs are located in the vertebrae of the spine and they are formed by highly compressible fibro cartilage. As for elastic cartilage this is found where a structure needs elasticity.
Areolar:
The most spread tissue within the body is called the areolar. The areolar is a soft tissue which protects the organs that it covers. It is a connective tissue that helps hold together helps hold the body organs together and help them stay in the correct position. The lamina propria is a soft layer of this type of tissue which triggers all mucous membranes. All types of fibres are found in its fluid. The areolar provides all of its surrounding tissues with reservoir water and salt due to its loose and fluid nature. All of the body’s cells gain their nutrients and release waste into the tissues fluid. When parts of the body become inflamed, the connective tissue areolar soaks up the excess fluid and the part then swells up, this is a condition called edema. Various types of phagocytes are found in this tissue, they pick up and destroy bacteria , dead cells and other derbis.
Adipose:
Adipose is the name given for fatty and it is made up of a variation of areolar tissues of which adipose cells have doubled several times in order to obscure other cells and fibres. Once the adipose cell has matured adipose cells are filled so much fat that the cell is pushed to one side. Adipose is usually found under the skin and in organs like the heart and the kidneys. Adipose is also found in external temperature, it also helps protect the body against energy and it also stores energy.
Muscle:
Muscle is a specialized tissue that can contract. Muscle tissue contains the specialized proteins actin and myosin that slide past one another and allow movement. Examples of muscle tissue are contained in the muscles throughout your body. There are three types of muscles which are striated, non-striated and cardiac.
Striated muscle:
Striated muscle is attached to the bones of the skeleton or some and some facial muscles are attached to the skin. Striated muscle is found in skeletal muscle. Skeletal muscle is called striated muscle because striations are seen on it through a microscope. The skeletal muscle is a voluntary muscle due to the fact that it has conscious control in moving the skeleton. A muscle is made up of many muscle fibres. The whole muscle is wrapped in connective tissue called the epimysium. Cells in the muscles are grouped together into separate groups and are called fascicules, which have connective tissues called perimysium. Inside the fascicles are muscles cells which are covered in connective tissue called the endomysium. All of the connective tissues wrap and cover the muscles whole length. They join together to form a structure and then combine with one another at the end of the muscle in order to form tendons, which is what attaches the muscle with the bone. The tissues that run throughout the muscle are vital as they transmit the speed of contraction from each cell to its target area within the skeleton. The name for the fleshy section of the skeleton is belly, when the muscle contracts this bulges and decreases in size.
Non-striated muscle:
Smooth muscle is an example non striated muscle. Smooth muscle is involuntary as there is no control over it. Smooth muscle is made up of very small cells which have one nucleus and are spindle shaped. In contrary to skeletal muscle, smooth muscle does not have a striped appearance on a microscope. Smooth muscle produces sheets in the walls of the body’s organs and tubular structures, so that it can control diameter and certain substances through tracts. Some smooth muscles are able to contract by itself through nerve stimulation. However sometimes hormones initiate contractions like adrenaline from the adrenal medulla, the adrenaline dilates the airways.
Cardiac muscle:
The cardiac muscle is found in the heart, this is because the heart pumps and drives blood through the blood vessels. The cardiac muscle has striations and the cells of this muscle are uninucleate. The cells of the cardiac muscle fit together closely at junctions which are called intercalated disks. These disks have junctions which contain gaps that let ions freely pass through from cell to cell. This then results in rapid conduction of the exciting electrical impulse across the heart.
Nervous:
The neurones and the neuroglia are two types of cells that are in the nervous system.
Neurones:
Neurones are excitable cells, they have the responsibility of instigating, receiving, conducting and sending out information. The structure of neurones consists of a cell body including its processes . an axon and various dendrites. Nerve cells are another name for neurones, when a range of axons combine together they then are called nerves.
Neuroglia:
Neuroglia are non-excitable cells which are used to support the neurones. There are four types of neuroglia, these are astrocytes, oligodendrocytes, microglia, and ependymal cells.
The role of tissues in the function of two named body organs:
The two named body organs that I am going to discuss are the cardiovascular system and the respiratory system.
The cardiovascular system:
Squamos epithelium cells are found on the walls of the blood capillaries. The blood contains connective tissues, red blood cells and white blood cells. The cardiovascular system consists of muscle tissues which are known as cardiac muscle tissues. The cardiac muscle tissue is only found in the walls of the heart. When this muscle is isolated from a nerve supply it is still able to contract and relax. The cardiac muscle cell is made from specialised cells called muscle fibres which are able to cause the heart to contract. The cardiac muscle is able to generate heat which helps regulate body temperature.
The heart is enclosed by a double walled sac called the pericardium. The outer wall is made of a dense, fibrous connective tissue that has the role of protecting the heart and it connects the nearby structures in the thorax for example the diaphragm and large blood vessels. The inner wall is a serous membrane made of two layers called the parietal and the visceral layers. Between these two walls is a cavity called the pericardial cavity. This cavity has a lubricating serous fluid which lets the heart beat in a reduced friction environment.
The hearts wall is made of three tissue layers these layers are:
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The epicardium- The epicardium is made of simple squamous epithelium, fibro-elastic connective tissue and within these there are imbedded nerves coronary blood vessels and adipose tissue. The simple squamous cells are what form the lining of the heart.
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The myocardium- This tissue layer is made up of cardiac myocyte layers that are fitted together by fibres of connective tissue. Collagen and elastin are what the connective tissue fibres are made of, together they produce a dense network that is called the fibrous skeleton of the heart. This works to try and reinforce the myocardium and provides an attachment surface for the cardiac muscles.
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The endocardium- This layer lines the lumen of the heart and is made up of simple squamous epithelium and a loose thin layer of connective tissue.
The heart valves are made of a skeleton of fibrous connective tissue, covered by endothelium. Endothelium cells produce the lining of the whole cardiovascular system, from the heart to the smallest capillary. Endothelium cells reduce the friction of blood flow so that the fluid can pump and deliver the blood further.
The respiratory system:
The alveoli has the form of a hollow cavity. The lung is the organ where alveoli are mainly found. The pulmonary alveoli is where the exchange of gases in the blood takes place. The alveoli have an epithelial layer and plasma which is surrounded by matrix. The alveolar cells consist of three main types of alveolar cells these type of cells are known as type1, type 2 and type 3. Type one cells are what make the structure if the alveolar wall. Type 2 cells release surfactant in order to lower the surface tension of water and play a role in the increase of gas exchange. Type 3 cells eradicate unknown cells such as bacteria.
The trachea which is also known as the wind pipe extends to bronchi from the larynx. Air travels through the trachea to get to the lungs. The lining of it consists of pseudostratified ciliated columnar epithelium cells that have mucosae goblet cells which are what produces mucus.
The nasal cavity also known as the nasal fossa is a large space that is found above and behind the nose, the space is filled with air. The areas of the respiratory tract receive air that has been conditioned by the nasal cavity. Due to the big surface area provided by the conchae. The air that goes through the nasal cavity is either warm or cooled within one degree of the body’s temperature. The air is then humidified. After this the dust and other particles are removed by the cilia, which are hairs that are found in the nostril. The cilia of the respiratory epithelium move the particulate matter towards the pharynx where it is swallowed.
Bibliography
Books:
- Marieb,E (2000) Essential of human anatomy and physiology, Addison Wesley Longman inc
- Waugh,A and Grant,A (2006) Anatomy and physiology in health and illness,Churchill livingstone
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