Topic 1 Its My Body Part 1 Cells

Topic 1: It’s My Body Part 1: Cells and Body Systems of Human, Homeostasis

PLANT CELL

ANIMAL CELL

Organelles : Function : Nucleus: Contains the DNA and RNA and manufactures proteins Nucleolus: In nuclei where ribosome are synthesized. Nuclear Envelope: Membrane of lipids and proteins that surrounds nucleu Centrioles: structure that appears du mitosis(cell division) Mitochondria: Energy producers of the cell Ribosomes: Produce proteins More Organelles

ORGANELLES FUNCTION Golgi Bodies: Packages Proteins Chloroplasts: Involved in photosynthesis Vacuoles: Store waste, nutrients, and water Lysosome: Contains digestive enzymes, mostly in animal cells Endoplasmic Reticulum: Passageway that transports proteins from the nucleus Rough ER covered in ribosomes,

WHILE NOT EXACTLY ORGANELLES, THE FOLLOWING ARE IMPORTANT PARTS OF THE CELLS: Cell membrane: lining the cell Cell Wall: the made of Cytoplasm: Semi-permeable that surrounds Is a stiff non-living wall that surrounds cell membrane cellulose Jelly-like material surrounding the organelles

Differences between unicellular and multicellular orgranisms. UNICELLULAR AND MULTICELLULAR ORGANISMS

UNICELLULAR ORGANISMS Most are microscopic Examples: Amoeba, Paramecia, E. Coli Perform the same tasks as multicellular organisms They move, eat, reproduce and expel waste.

THE AMOEBA

Binary Fission (cell division) PARAMECIA

THE AMOEBA Have characteristics of an animal cell Live in fresh and salt water environments and decaying vegetation sites. Are predators – they prey on algae and bacteria Uses osmosis to get water and diffusion to get oxygen and dispose of carbon dioxide.

MULTICELLULAR ORGANISMS Rely on a variety of cells to perform cellular functions. These are called “specialized cells”. Specialized cells perform duties such as digestion or movement. Example: Eyes, Muscles and Tongue. (what duties do these perform? ) Cells can be compared to small cities. Each one performs a different job/function. They all work together to be efficient. Just like we need specialist doctors, cells need specialist cells.

How is the body organized? Each specific cell is grouped with cells similar in structure and function to form a tissue. cells tissue

Examples of tissue Animal tissues Plant tissues muscle mesophyll bone phloem liver skin lung Can you think of any more types of tissue? xylem

How is the body organized? Groups of tissues Cells are the Groups of cells basic units of life. cell work together to form tissues. tissue work together to form organs. organ

How is the body organized? Groups of organs form systems. For example, the human digestive system is made up of several organs including the mouth, gullet, stomach and small intestine. The different organs in a system are linked together by tubes or vessels. What other human body systems can you think of?

Tissues in the Human Body � Epithelial ◦ Covering or lining tissue Connective ◦ Joins, stores and supports � Muscle ◦ Internal and external movement � Nerve ◦ Conducts electrical signals Blood � Muscle Nerve

How is the body organised? Why do organisms have to be so organised? Organisation of the body allows complex organisms to carry out many different jobs at the same time. respond to things body life processes grow reproduce move respire digest food excrete Being organised means that the body does not waste energy, so it is more efficient.

Human Organ Systems Skeletal Circulatory Respiratory Excretory Nervous Integumentary Muscular Immune Digestive Reproductive Endocrine

Matching systems and organs

How the body response to the changes? The conditions inside and outside our body are always changing. Some of these changes can be harmful. The two organ systems helps body to adjust to these changes are: • The nervous systems uses electrical signal to response to changes • The hormonal system also coordinate some of the body’s responses, using hormones. This maintenance of a constant internal environment despite changes in the surroundings is called homeostasis.

Stimulus and Response.

Flow chart of stimulus-response

Homeostasis: Regulating the Internal Environment �A controlled, stable internal environment �Gains and losses must balance �Control systems ◦ Receptor, control centre, effector ◦ Feedback loops �Negative feedback �Positive feedback

All internal organs contribute to homeostasis, but this lab examines the contributions of the lungs, kidneys, and liver.

Pancreatic Hormones, Insulin and Glucagon, Regulate Metabolism

Blood glucose regulation Glucose is needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. Insulin is a hormone produced by the pancreas that regulates glucose levels in the blood.

How glucose is regulated? Effect on Glucose level pancreas too high too low Hormone insulin secreted into the blood insulin not secreted into the blood (instead another hormone glucagon is secreted) Effect on liver Effect on glucose level liver converts glucose into glycogen goes down liver does not convert glucose goes up into glycogen

Glucagon �The pancreas releases another hormone, glucagon, when the blood sugar levels fall. This causes the cells in the liver to turn glycogen back into glucose which can then be released into the blood. The blood sugar levels will then rise.

� http: //www. bbc. co. uk/schools/gcsebitesize/science/edex cel/responses_to_environment/homeostasisrev 6. shtml

Homeostasis – Negative Feedback �The control of blood sugar (glucose) by insulin is another good example of a negative feedback mechanism. When blood sugar rises, receptors in the body sense a change. In turn, the control center (pancreas) secretes insulin into the blood effectively lowering blood sugar levels. Once blood sugar levels reach homeostasis, the pancreas stops releasing insulin.

Homeostasis – Positive Feedback �A good example of a positive feedback mechanism is blood clotting. Once a blood vessel is damaged, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed.

�Glucose homeostasis – Putting it all together (extra notes) Insulin Beta cells of pancreas stimulated to release insulin into the blood High blood glucose level STIMULUS: Rising blood glucose level (e. g. , after eating a carbohydrate-rich meal) Body cells take up more glucose Liver takes up glucose and stores it as glycogen Homeostasis: Normal blood glucose level (about 90 mg/100 m. L) Blood glucose level rises to set point; stimulus for glucagon release diminishes Figure 26. 8 Blood glucose level declines to a set point; stimulus for insulin release diminishes Liver breaks down glycogen and releases glucose to the blood STIMULUS: Declining blood glucose level (e. g. , after skipping a meal) Alpha cells of pancreas stimulated to release glucagon into the blood Glucagon

Liver/Blood Sugar Regulation (extra notes) The body requires volumes of glucose in order to create ATP. The amount of ATP demanded will fluctuate, and therefore the body regulates the availability of glucose to maximize its energy making potential. Two hormones are responsible for controlling the concentration of glucose in the blood. These are insulin and glucagon. The diagram illustrates the principle of negative feedback control in action involving blood/sugar levels. http: //bioserv. fiu. edu/~walterm/human_online/lab s/homeostasis. htm

Liver/Blood Sugar Regulation (extra notescontinue…) The level of glucose in the bloodstream drops The person requires glucose in cells to meet the demand for ATP The body detects this with a particular receptor designed for this function These receptors release hormones, chemical messages that initiate the start of the feedback mechanism The hormones travel to their target tissue and initiate a corrective response In this case, the corrective response is the secretion of more glucose into the bloodstream

Homeostasis (extra notes) Homeostasis means “steady state, ” or internal balance, and is a recurrent theme in understanding how organisms function as a whole. A stable environment, maintained within narrow limits, is essential to all life. Organisms constantly exchange energy and materials with their environments. The gains and losses must balance over some type of time interval. For example, as glucose enters the blood after a meal, excess glucose is transported to the liver to be converted to glycogen. Between meals, as glucose levels drop, the liver converts glycogen back to glucose and releases it into the bloodstream.

Homeostasis (extra notes continue) Homeostatic control systems have a receptor that detects change, along with a control center that directs the response to an effector. The body monitors internal conditions and makes corrections through biofeedback loops. In negative feedback loops, a change in the monitored variable triggers a response to counteract further change in the same direction. If excess heat is detected in the body, the brain signals the blood vessels near the surface of the body to dilate and the sweat glands to increase production. As body temperature nears normal, the brain reverses the process by slowing sweat production and constricting blood vessels. In positive feedback loops, a change in the monitored variable triggers further action rather than reversing the action. A common example of a positive feedback loops occurs in blood clotting, with each clotting reaction activating another until the bleeding is stopped

Homeostasis (maintaining balance) Task: Write a letter to a relative : �explaining how they have just been diagnosed with diabetes. �Describe what changes that will bring to their lives and consequences of not controlling the disease properly: http: www. diabetesaustralia. com. au/

Maintaining Balance Homeostasis �Insulin and glucagon are hormones that work to regulate the level of sugar (glucose) in the body to keep it within a healthy range. �Diabetes is a disorder of metabolism— the way the body uses digested food for energy. People with diabetes have high glucose levels in their blood.

Diabetes Type 1 diabetes and Type 11 diabetes �Type 1 diabetes develops when pancreas stops producing insulin. �Type 2 diabetes develops when pancreas can no longer produce enough insulin

It’s my body (part 1) cells, organisms, body systems and maintaining balance summary � Stimulus- change in environment (internal and external. E. g. Light is a stimulus from external environment. Changes in glucose level is another stimulus � Receptors – specialised cells that can detect changes in environment. E. g. Photoreceptors in the eye retina detect light (a stimulus) � Effectors – any part of the body that produces response. E. g. examples of effectors: � a muscle contracting to move the arm � a muscle squeezing saliva from the salivary gland � a gland releasing a hormone into the blood

It’s my body (part 1) cells, organisms, body systems and maintaining balance summary � Hormones: - chemicals secreted by endocrine glands in organs. E. g. insulin by pancreas and thyroxin by thyroid glands. � Homeostasis: -physiological system of multi-cellular organisms, to maintain internal stability, owing to the coordinated response of its parts to any situation or stimulus that would tend to disturb its normal condition or function. E. g. Blood glucose regulation by hormones such as insulin/glucagon. � Insulin: - a hormone that lowers the level of glucose. Insulin is secreted by the pancreas. � Glucagon: - A hormone produced by the pancreas that stimulates an increase in blood sugar levels, thus opposing the action of insulin.