topic 1: it’s my body part 1: cells and body systems of human, homeostasis
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Topic 1: It’s My BodyPart 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 ribosomes are synthesized.
Nuclear Envelope: Membrane of lipids and proteins that surrounds
nucleusCentrioles: structure that appears
during mitosis(cell division)
Mitochondria: Energy producers of the cellRibosomes: Produce proteins
More Organelles
ORGANELLES FUNCTIONGolgi Bodies: Packages ProteinsChloroplasts: Involved in
photosynthesisVacuoles: Store waste,
nutrients, and water
Lysosome: Contains digestive enzymes,
mostly in animal cells
Endoplasmic Reticulum:Passageway that transports proteins from
the nucleusRough ER covered in
ribosomes, Smooth ER is not!
WHILE NOT EXACTLY ORGANELLES, THE FOLLOWING ARE IMPORTANT PARTS OF THE CELLS:
Cell membrane: Semi-permeable lining that surrounds the cell
Cell Wall: Is a stiff non-living wall that surrounds the
cell membrane made of cellulose
Cytoplasm: Jelly-like material surrounding the organelles
UNICELLULAR AND MULTICELLULAR ORGANISMS
Differences between unicellular and multicellular orgranisms.
UNICELLULAR ORGANISMS
Most are microscopic Examples: Amoeba, Paramecia, E. Coli Perform the same tasks as multicellular
organisms They move, eat, reproduce and expel
waste.
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.
Each specific cell is grouped with cells similar in structure and function to form a tissue.
How is the body organized?
cells tissue
Animal tissues Plant tissues
muscle
bone
liver
skin
lung
mesophyll
phloem
xylem
Can you think of any more types of tissue?
Examples of tissue
Groups of tissues work together to form organs.
How is the body organized?
cell tissue organ
Groups of cells work together to form tissues.
Cells are thebasic units oflife.
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?
How is the body organized?
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
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.
How is the body organised?
Being organised means that the body does not waste energy, so it is more efficient.
grow
reproduce
respond to things
excrete
respire
move digest food
body life processes
Human Organ Systems
Skeletal MuscularCirculatory ImmuneRespiratory DigestiveExcretory
ReproductiveNervous EndocrineIntegumentary
Matching systems and organs
• 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 environmentdespite changes in the surroundings is calledhomeostasis.
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:
Stimulus and Response .
Flow chart of stimulus-response
Homeostasis: Regulating the Internal EnvironmentA controlled, stable internal
environment Gains and losses must balanceControl 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.
Glucose levelEffect on pancreas Effect on liver
Effect on glucose level
too high
Hormone insulin secreted into the blood
liver converts glucose into glycogen
goes down
too low
insulin not secreted into the blood (instead another hormone glucagon is secreted)
liver does not convert glucose into glycogen
goes up
How glucose is regulated?
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/edexcel/responses_to_environment/homeostasisrev6.shtml
Homeostasis – Negative FeedbackThe 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 FeedbackA 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)
Figure 26.8
Insulin
Beta cellsof pancreas stimulatedto release insulin intothe blood
Bodycellstake up moreglucose
Blood glucose leveldeclines to a set point;stimulus for insulinrelease diminishes
Liver takesup glucoseand stores it asglycogen
High bloodglucose level
STIMULUS:Rising blood glucoselevel (e.g., after eatinga carbohydrate-richmeal) Homeostasis: Normal blood glucose level
(about 90 mg/100 mL) STIMULUS:Declining bloodglucose level(e.g., afterskipping a meal)
Alphacells ofpancreas stimulatedto release glucagoninto the blood
Glucagon
Liverbreaks downglycogen and releases glucoseto the blood
Blood glucose levelrises to set point;stimulus for glucagonrelease diminishes
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/labs/homeostasis/homeostasis.htm
Liver/Blood Sugar Regulation (extra notes- continue…)
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 - HomeostasisInsulin 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 diabetesType 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
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.
It’s my body (part 1) cells, organisms, body systems and maintaining balance - summary
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