1. Cells, Tissues & Organs - National 5 Biology
These are organized into tissues; the tissues into organs. View showing relationship between the apical and basolateral surfaces of epithelial cells and how. Animals and plants are made of cells. Tissues are made from cells of a similar type. Organs are made from tissues, and systems are made from several organs . Epithelial tissues cover the outside of organs and structures in the body and .. the next and maintains the strong connection between neighboring cardiac cells.
Tissues, organs, & organ systems (article) | Khan Academy
The endocrine system is the second type of extrinsic control, and involves a chemical component to the reflex. Sensors detect a change within the body and send a message to an endocrine effector parathyroidwhich makes PTH.
PTH is released into the blood when blood calcium levels are low. PTH causes bone to release calcium into the bloodstream, raising the blood calcium levels and shutting down the production of PTH. Some reflexes have a combination of nervous and endocrine response. The thyroid gland secretes thyroxin which controls the metabolic rate into the bloodstream.
Falling levels of thyroxin stimulate receptors in the brain to signal the hypothalamus to release a hormone that acts on the pituitary gland to release thyroid-stimulating hormone TSH into the blood. TSH acts on the thyroid, causing it to increase production of thyroxin. Intrinsic Local, or intrinsic, controls usually involve only one organ or tissue. When muscles use more oxygen, and also produce more carbon dioxide, intrinsic controls cause dilation of the blood vessels allowing more blood into those active areas of the muscles.
Eventually the vessels will return to "normal". Feedback Systems in Homeostasis Back to Top Negative feedback control mechanisms used by most of the body's systems are called negative because the information caused by the feedback causes a reverse of the response.
TSH is an example: Positive feedback control is used in some cases. Input increases or accelerates the response. During uterine contractions, oxytocin is produced. Oxytocin causes an increase in frequency and strength of uterine contractions. This in turn causes further production of oxytocin, etc. Homeostasis depends on the action and interaction of a number of body systems to maintain a range of conditions within which the body can best operate.
Body Systems and Homeostasis Back to Top Eleven major organ systems are present within animals, although some animals lack one or more of them. The vertebrate body has two cavities: The head, or cephalic region, contains four of the five senses as well as a brain encased in the bony skull.
These organ systems can be grouped according to their functions. The integumentary, skeletal, and muscular systems. Image from Purves et al. Muscular System shown in Figure 1 facilitates movement and locomotion. The muscular system produces body movements, body heat, maintains posture, and supports the body.
Muscle fibers are the main cell type. Action of this system is closely tied to that of the skeletal system.Tissues, Part 1: Crash Course A&P #2
Skeletal System shown in Figure 1 provides support and protection, and attachment points for muscles. The skeletal system provides rigid framework for movement. It supports and protects the body and body parts, produces blood cells, and stores minerals.
Skin or Integument shown in Figure 1 is the outermost protective layer. It prevents water loss from and invasion of foreign microorganisms and viruses into the body. There are three layers of the skin. The epidermis is the outer, thinner layer of skin. Basal cells continually undergo mitosis. Skin is waterproof because keratin, a protein is produced.
The next layer is the dermis a layer of fibrous connective tissue. Within the dermis many structures are located, such as sweat glands, hair follicles and oil glands. The subcutaneous layer is composed of loose connective tissue. Adipose tissue occurs here, serving primarily for insulation. Nerve cells run through this region, as do arteries and veins. The digestive and respiratory systems. Respiratory System moves oxygen from the external environment into the internal environment; also removes carbon dioxide.
The respiratory system exchanges gas between lungs gills in fish and the outside environment. It also maintains pH of the blood and facilitates exchange of carbon dioxide and oxygen.
The system is summarized in Figure 2. Digestive System digests and absorbs food into nutrient molecules by chemical and mechanical breakdown; eliminates solid wastes into the environment. Digestion is accomplished by mechanical and chemical means,breaking food into particles small enough to pass into bloodstream.
Absorbtion of food molecules occurs in the small intestine and sends them into circulatory system. The digestive system also recycles water and reclaims vitamins from food in the large intestine. The circulatory and lymphatic systems.
Circulatory System Figure 3 transports oxygen, carbon dioxide, nutrients, waste products, immune components, and hormones. Major organs include the heart, capillaries, arteries, and veins. The lymphatic system also transports excess fluids to and from circulatory system and transports fat to the heart. Immune System Lymphatic system, Figure 3 defends the internal environment from invading microorganisms and viruses, as well as cancerous cell growth.
A variety of general responses are also part of this system. Excretory System regulates volume of internal body fluids as well as eliminates metabolic wastes from the internal environment. The excretory system removes organic wastes from the blood, accumulating wastes as urea in the kidneys. These wastes are then removed as urine. Contraction of smooth muscle fibres occurs without the conscious control of the animal.
Skeletal muscle fibres Skeletal muscle[ edit ] Skeletal muscle sometimes called striated, striped or voluntary muscle has striped fibres with alternating light and dark bands.
Anatomy and Physiology of Animals/Body Organisation
It is attached to bones and is under the voluntary control of the animal see diagram 4. Cardiac muscle cells are branched cylinders with central nuclei and faint stripes see diagram 4.
Each fibre contracts automatically but the heart beat as a whole is controlled by the pacemaker and the involuntary autonomic nervous system. A motor neuron Nervous Tissues[ edit ] Nervous tissue forms the nerves, spinal cord and brain.
Tissues, organs, & organ systems
Nerve cells or neurons consist of a cell body and a long thread or axon that carries the nerve impulse. An insulating sheath of fatty material myelin usually surrounds the axon. Vertebrate Bodies[ edit ] We are so familiar with animals with backbones i. There is a well-defined head that contains the brain, the major sense organs and the mouth, a trunk that contains the other organs and a well-developed tail.
Other features of vertebrates may be less apparent. For instance, vertebrates that live on the land have developed a flexible neck that is absent in fish where it would be in the way of the gills and interfere with streamlining.
Mammals but not other vertebrates have a sheet of muscle called the diaphragm that divides the trunk into the chest region or thorax and the abdomen. Body Cavities[ edit ] Diagram 4. The body cavities In contrast to many primitive animals, vertebrates have spaces or body cavities that contain the body organs.
Most vertebrates have a single body cavity but in mammals the diaphragm divides the main cavity into a thoracic and an abdominal cavity.
In the thoracic cavity the heart and lungs are surrounded by their own membranes so that cavities are created around the heart - the pericardial cavity, and around the lungs — the pleural cavity see diagram 4.
Organs[ edit ] Diagram 4. For example, connective tissues, epithelial tissues, muscle tissue and nervous tissue combine to make the organ that we call the stomach. In turn the stomach combines with other organs like the intestines, liver and pancreas to form the digestive system see diagram 4.
The main organs of the vertebrate body At this point it would be a good idea to make yourself familiar with the major organs and their positions in the body of a mammal like the rabbit.
Body Systems[ edit ] Organs do not work in isolation but function in cooperation with other organs and body structures to bring about the MRS GREN functions necessary to keep an animal alive. For example the stomach can only work in conjunction with the mouth and oesophagus gullet. These provide it with the food it breaks down and digests.
ANIMAL ORGAN SYSTEMS
It then needs to pass the food on to the intestines etc. The organs involved with the taking of food into the body, the digestion and absorption of the food and elimination of waste products are collectively known as the digestive system.
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- Cells in the Human Body
The 11 body systems[ edit ] Skin The skin covering the body consists of two layers, the epidermis and dermis. Associated with these layers are hairs, feathers, claws, hoofs, glands and sense organs of the skin.
Skeletal System This can be divided into the bones of the skeleton and the joints where the bones move over each other. Muscular System The muscles, in conjunction with the skeleton and joints, give the body the ability to move. Cardiovascular System This is also known as the circulatory system. It consists of the heart, the blood vessels and the blood. It transports substances around the body.
This fluid is then returned to the blood system. The lymphatic system also makes antibodies that protect the body from invasion by bacteria etc.
It consists of lymphatic vessels, lymph nodes, the spleen and thymus glands. Respiratory System This is the system involved with bringing oxygen in the air into the body and getting rid of carbon dioxide, which is a waste product of processes that occur in the cell. It is made up of the trachea, bronchi, bronchioles, lungs, diaphragm, ribs and muscles that move the ribs in breathing.
Digestive System This is also known as the gastrointestinal system, alimentary system or gut. It consists of the digestive tube and glands like the liver and pancreas that produce digestive secretions. It is concerned with breaking down the large molecules in foods into smaller ones that can be absorbed into the blood and lymph.
Waste material is also eliminated by the digestive system. Urinary System This is also known as the renal system. It removes waste products from the blood and is made up of the kidneys, ureters and bladder.
Reproductive System This is the system that keeps the species going by making new individuals. It is made up of the ovaries, uterus, vagina and fallopian tubes in the female and the testes with associated glands and ducts in the male. Nervous System This system coordinates the activities of the body and responses to the environment. It consists of the sense organs eye, ear, semicircular canals, and organs of taste and smellthe nerves, brain and spinal cord.
Endocrine System This is the system that produces chemical messengers or hormones.
It consists of various endocrine glands ductless glands that include the pituitary, adrenal, thyroid and pineal glands as well as the testes and ovary. Homeostasis[ edit ] All the body systems, except the reproductive system, are involved with keeping the conditions inside the animal more or less stable. This is called homeostasis. These constant conditions are essential for the survival and proper functioning of the cells, tissues and organs of the body.
The skin, for example, has an important role in keeping the temperature of the body constant. The kidneys keep the concentration of salts in the blood within limits and the islets of Langerhans in the pancreas maintain the correct level of glucose in the blood through the hormone insulin. As long as the various body processes remain within normal limits, the body functions properly and is healthy. Once homeostasis is disturbed disease or death may result. See Chapters 12 and16 for more on homeostasis.
The directional terms used with animals Diagram 4. Transverse and longitudinal sections of a mouse In the following chapters the systems of the body in the list above will be covered one by one.
For each one the structure of the organs involved will be described and the way they function will be explained. In order to describe structures in the body of an animal it is necessary to have a system for describing the position of parts of the body in relation to other parts. For example it may be necessary to describe the position of the liver in relation to the diaphragm, or the heart in relation to the lungs.
Certainly if you work further with animals, in a veterinary clinic for example, it will be necessary to be able to accurately describe the position of an injury. The terms used for this are called directional terms.