The Feedback System and Negative Feedback
1. When have you used the scientific method, or perhaps certain aspects of the scientific method, in your life? Are there other fields besides physiology in which the scientific method is useful? How could you apply the method to your daily life? Please see the chapter review for section 1.5 on page 17 of the customized textbook for a description of the scientific method.
2. To learn about body functions, scientific methods have to be systematic. The steps used in this method are making an observation, formulating the hypothesis, testing the hypothesis using a designed experiment, and interpreting the data obtained.
3. The fields that use scientific methods other than psychology are; journals, the internet, and the production of books. We can also use this method to apply it in our daily lives. For instance, we can observe the clouds to determine the weather, formulate a hypothesis by deciding what to wear accordingly and experiment with the hypothesis by getting outside in clothes chosen.
4. Define a feedback system. What is a controlled variable?
A feedback system refers to a cycle of events in which internal environmental parameter is evaluated, monitored, changed, reevaluated, and monitored. In this case, the controlled variable is in each monitored parameter. The controlled variables are; blood PH, blood pressure, body oxygen content, body temperature, and blood glucose level.
1. Receptors- receptors monitors changed from the controlled variable and then sent information to the control center.
2. The Control center receives input and generates output. Our brain acts as a control center.
3. Effector functions by changing the controlled center and then affects the changes in the controlled variable or produces the response
4. Explain the negative feedback loop between baroreceptors, the cardiovascular (CV) center, and the heart. Address dropping blood pressure, heart stimulation, and hormonal vessel constriction. How do these all work together to achieve homeostasis?
Negative feedback is a negative change in the controlled variable. The negative feedback between the cardiovascular center, baroreceptors, and the heart occurs when the internal and external factors cause the blood pressure to rise. When the heart rate decreases, the blood vessels dilate, which causes the blood pressure to decrease. On the other hand, baroreceptors detect the high pressure in blood vessels and send the action potential in the brain, which then interprets the electrical signals, sending the output to the blood vessels and the heart. When this happens, the blood pressure returns to normal, negating the previous stimulus, a negative feedback system.
Proteins are constructed from amino acids. They give structure to the body, regulate processes, provide protection, help muscles contract, transport substances, and serve as enzymes
5. Describe the following enzyme characteristics:
6. Specificity- Made of proteins – The dimensional shape of the enzymes, which are more than 1000 in our bodies, allows binding in particular substrates, which helps control reactions in the body by matching to specific substrates. The enzymes recognize the correct substrates, separate them, and merge them with another substrate to form a particular product.
Enzymes and Their Functions
1. Efficiency- When produced in an ideal condition, the enzymes are very efficient as they can catalyze a reaction 10billion times faster. Enzymes help in making the responses faster and more efficient.
2. Regulation- Some enzymes regulate biochemical reactions by acting as a catalyst.
3. Gene control- Gene information is mainly kept by enzymes that decide to release and bind them to a specific site. When this process does not happen, mutation can occur
4. Inhibition- End product inhibition is referred to as specific enzymes meant to stop the reaction. For instance, feedback inhibition occurs when enzymes stop the response of the metabolic pathway.
5. Your best friend decides to begin frying his eggs in margarine instead of butter because he heard that eating butter is bad for his heart. Is this a wise choice? Are there other alternatives?
When kept at room temperature, fat is a solid-state where its fatty acids are primarily saturated. In their hydrocarbon chain, these saturated fatty acids do not have double bonds. Saturated fats are present in butter. On the other hand, these fatty acids are primarily unsaturated.
6. What are the functions of water in the human body?
Polarity makes water an ideal solvent for polar substances and iconic, too, as it gives cohesion to water molecules allowing it to resist temperature changes. Therefore, close to all chemical reactions in the body requires a watery medium; hence one can not survive without taking water for several days.
Water acts as a lubricant. Throughout the body, water is the main component of mucus and other lubricating fluids. Where internal organs slide and touch another, a lubricant is required to avoid friction which, without, is fatal, as they could damage each other
8. What is your favorite organelle? Why is it your favorite? Imagine what the cell would be like without that particular organelle, and describe how that cell would be able to function (or not) without your chosen organelle.
Ribosomes are my favorite organelle as it is the site for protein synthesis. They are high in rRNA, and their structure has two subunits; small and large, and both are made in the nucleus but the cytoplasm.
There are the free and bound ribosomes. Free is not attached to the cytoplasm, which is bound to the outer ring of the nucleus and endoplasmic reticulum. Ribosomes are my favorite as they are in charge of synthesizing and transporting proteins. Without them, there would be no growth, and where there is no growth, there is no life.
9. How do membrane proteins perform the following functions? Provide one example each for a. and b.
10. Communication- Plasma membrane plays a crucial role in communicating between inside the cells and their external environment. It separates the exterior and the internal climate, only allowing the movement of certain permeable and semi-permeable fluids.
Enzymes act as a catalyst in specific chemical reactions in the body, either outside or inside the cell surface. They also allow the movement of materials into the cells. Other enzymes oxidize hydrogen atoms from organic substances.
Effect of Fats on Heart Health
The plasma membrane identifies a variety of external stimuli since these stimuli have receptors that serve as cellular sites for recognition. To place a particular cell by cell membrane is through the presence of glycoprotein and glycolipids that act as cell-identity markers. They permit the cell membrane to identify safe and dangerous cells, such as blood transfusion, which requires identification to allow the blood transfusion.
These are web-like strands of transmembrane proteins that seal off passageways between adjacent cells. These junctions help prevent the organ contents from leaning into the surrounding tissues. The tissues with many tight corners are; epithelial tissues lining the stomach, urinary bladder, and intestines.
Plasma membranes of gap junctions are not joined together but have intercellular gaps called connexins connected to the neighboring cells. These connexin ions and small molecules diffuse and form cytosol from one cell to another.
10. Compare and contrast apoptosis with necrosis.
Apoptosis is programmed and normal death cells. They happen first during the embryo’s development and progress throughout the life of an organism.
Necrosis is the opposite of apoptosis as it is a pathological cell death type that results from an injured tissue leading to the swell of the cells, which bursts into the fluids.
11. Briefly describe:
12. Anaerobic glycolysis.
Glycolysis is a set of cytosolic reactions that convert one glucose molecule into two pyruvic acid molecules and produce ATP. Anaerobic glycolysis occurs when glycolysis does not require oxygen and occurs under aerobic or anaerobic the lack of oxygen conditions. In the absence of oxygen or at low oxygen concentrations, the pyruvic acid generated during glycolysis is converted to lactic acid, and cellular respiration does not occur.
1. (Catabolize-breakdown of food proteins into amino acids. Or the dissection of a complex chemical substance into simpler constituents)
2. Ketogenesis occurs when the liver converts some acetyl CoA molecules into ketone bodies due to fatty acid catabolism. Ketogenesis is the process by which these ketone bodies are formed.
3. Where lipogenesis occurs.
Anabolism is how complex chemical substances are created from smaller components.
Lipogenesis is the process by which liver and adipose cells synthesize lipids. It occurs when a person consumes more calories than is required to meet their ATP needs and an excess of dietary carbohydrates, protein, and fat. This condenses to form triglycerides.
1. How fatty acids are anabolized (built).
Lipogenesis is the process by which fatty acids or triglycerides are produced.
Acetyl CoA-fatty acid-amino acids-keto acids-acetyl
1. How glycerol is anabolized.
The use of glucose to form lipids occurs in two pathways. The resulting glycerol and fatty acids can undergo anabolic reactions to become stored triglycerides. They can undergo anabolic reactions to create lipids such as lipoproteins, apolipids, and cholesterol.
1 Glucose-glyceraldehyde-3-phosphate-glycerol and
2 Glucose-glyceraldehyde-3-phosphate-pyruvic acid-acetyl CoA-fatty acids
1. How are anabolized.
Anabolism is how complex chemical substances are created from smaller components. Triglycerides and phospholipids are the byproducts of amino acid and glucose anabolism.
High-protein, low-carbohydratediets like the Atkins diet are often called ketogenic After reading this chapter, can you explain why? What might be a good reason to go on a diet like this? What might be a good reason not to go on a diet like this?
The Functions of Water in the Human Body
After reading this fascinating chapter about the body’s essential molecules, I believe that one should not diet at all but consume the proper amount of calories required for proper functioning. Carbohydrates are just as important as protein when following a keto or Atkins diet. However, suppose you want to do a keto diet. You must be very careful with the number of carbs you consume for the following reasons: Sugars, glycogen, starches, and cellulose are examples of carbohydrates.
A limited amount of carbohydrate is stored as glycogen in the liver and skeletal muscles, accounting for 2-3% of our body mass. Carbohydrates are required for ATP degeneration, which is needed for various chemical reactions, such as constructing structural units of DNA, the type of sugar that carries inherited genetic information. Carbohydrates come in different sizes due to their carbon -mon, disac, and polysaccharides. Starch is a polysaccharide derived from plants. Potatoes and grains contain it. Hydrolysis reactions break down starch into monosaccharides. When blood glucose levels fall, liver cells break down glycogen into glucose and release it into the bloodstream, making it available to body cells, breaking it down to synthesize ATP. Cellulose is a polysaccharide derived from glucose by plants that cannot be digested by humans but provides bulk to aid in eliminating feces.
Proteins are large molecules of carbon, hydrogen, oxygen, and nitrogen- an adult I s12-18 protein. The primary function of proteins comes with many responsibilities: the structure of body tissues. Proteins perform functions such as regulators, contractors, immunoliors, transporters, and catalyzers.
What real-life situations could lead to crenation of your blood cells? What about hemolysis? Describe a situation in your life or a situation you have heard about in which someone has experienced or has come close to sharing one of these processes.
Crenation occurs when cells lose water or fluids due to osmosis or other erubtion.
Hemolysis occurs when erythrocytes rupture and leak, resulting in hemoglobin release into the plasma. So far, I have not had any real-life experiences. Still, I have heard of many people receiving the worng body types during transfusions when the incorrect transfusion results in agglutination or clumping. As a result of hemolysis, the erythrocytes rupture, releasing hemoglobin into the plasma.
Briefly describe each of the following plasma membrane functions:
Importing- A specific ion can flow across the plasma membrane via an ion channel from a pore in the plasma membrane. Most membranes have particular channels for a variety of common ions. Take in some ions to aid in chemical reactions.
Exporting- transport a specific substance across a membrane by undergoing a shape change. As amino acids are required to synthesize proteins, they enter body cells via carries. Carrier proteins are also referred to as transporters..
Communicating- The plasma membrane connects the cell’s outside and inside surfaces. It is a selective barrier that allows the material to flow into and out of a cell, establishing and maintaining a proper environment for cell activity. It communicates between cells as well as between cells and their surroundings.
Ribosomes and Protein Synthesis
Contrast each of the following types of endocytosis and describe how each is used by cells.
Monocytes, a type of leukocyte, form by engulfing bacteria and cellular debris. Macrophages are another name for macrophages.
Filtration of fluid – tubular reabsorption (urine excretion) The majority of filtered water and many filtered solvents form the bloodstream. Reabsorption is carried out by the renal tubule and collecting duct after the nephron has filled with 99 percent of the water. Pinocytosis is when small proteins and peptides that pass through the filter are reabsorbed. The receptors are integral membrane proteins concentrated in clathrin-coated pits of the plasma membrane. Clathrin, a protein, attaches to the membrane on its cytoplasmic side. Many clathrin molecules combine to form a basketlike structure around the receptor–LDL complexes, causing the membrane to invaginate ( fold inward). 2 The formation of cysts. The membrane’s invaginated edges fuse around the clathrin-coated pit, and a small piece of membrane pinches off. The receptor–LDL complexes are found in the resulting cyst, a clathrin-coated vesicle—3 Uncoating. The clathrin-coated vesicle loses its clathrin coat almost immediately after formation to become an uncoated vesicle. Clathrin molecules either return to the plasma membrane’s inner surface or aid in constructing coats on other vesicles within the cell.
It is a highly selective type of endocytosis in which extracellular fluid ligands bind to plasma membrane receptor proteins, resulting in plasma membrane vesicles. The binding of a specific ligand to a particular receptor is highly selective. As an illustration, consider the following example of low-density lipoprotein uptake:
Binding- LDL forms a receptor-LDL complex when it binds to a specific receptor on the extracellular side of the plasma membrane. These receptors are concentrated on the cytoplasmic side in clathrin-coated pits. Clathrin molecules bind together and cause membrane invagination, causing the membrane to fold inward.
Vesicle formation- the inward folding causes the edges to fuse, resulting in vesicle formation, also known as Clathrin-coated vesicle. LDL is found within the vesicle.
Uncoating- after vesicle formation, Clathrin molecules are removed and recycled, resulting in an uncoated vesicle.
Have you ever heard of someone becoming less sensitive to something due to increased exposure to it? Provide an example of this. Do you think it could be the result of down-regulation?
Explain. As an example, imagine putting your feet in cold water and eventually not feeling the cold.
When you receive an excessive amount of hormone and neurotransmitter, you lose the receptor’s response, referred to as down-regulation.
If a stimulus is very small, it may only trigger a small graded potential in the sensory neuron. Can you think of a time when a stimulus was so small you didn’t even detect it? Why does a small graded potential result in no signal being sent? What would need to happen for you to detect the stimulus?
A tiny stimulus can only trigger a small graded potential. Sometimes, no stimulus is due to subthreshold stimulus, which means it does not have the minimum stimuli to start an action potential or get the trigger for any action. A small stimulus, such as a fly flying over your head, can be received by your hearing receptors, but when it is sent to the central nervous system, it is deemed insufficient to prompt action and is ignored. A considerable grader potential requires a significant stimulus or, at the very least, a stimulus that is just strong enough in response to a threshold stimulus. A minimum number of stimuli must be detected to initiate a graded potential. Because the local current flow occurs as depolarized, a more potent stimulus causes a more significant graded potential than a weaker stimulus.
Membrane Proteins and Their Functions
Where is each of the following types of gated channels located, and what function does each of these channels serve?
Ligand-gatedchannels are found in sensory neuron dendrites in pain receptors and entries and cell bodies of interneurons and motor neurons. They open in response to the chemical stimulus of ligand binding.
- Voltage-gated- These channels are found on the axons of all types of neurons and open in response to voltage stimulation.
- Mechanically-gated- These channels are found on the dendrites of specific sensory neurons. On touch receptors, pressure receptors, and some pain receptors are activated in response to a mechanical stimulus such as touch, pressure, or tissue stretching
Neurotransmitters cause postsynaptic ion channels to open. Explain how this can lead to either a graded depolarizing potential or a hyperpolarizing graded potential.
Depolarizing grade potential occurs near the axon terminal or in the axon trigger zone. Making the inside of the cell more favorable for the action potential is what depolarization entails. The synaptic end cell membrane contains voltage-gated Ca2+ channels in addition to Na+ and K+. The depolarizing phase of the action potential activates the Na+ channels, which rushes the Na+ into the cell membrane and causes it to become more positive. The threshold (-50 mv) increases to +30 mv, further opening the Ca+ channels; the Ca+ channels are more concentrated in the extracellular fluid, and Ca2+ flows inward through open voltage Ca2 channels. The increase in Ca+ concentration within the synaptic end serves as a single that triggers exocytosis- two protein linking and synaptic fussion with cell membrane and neurotransmitter which may bind to the next neuron.
Choose a cranial nerve and describe its functions. Is it a sensory, motor, or mixed nerve? What do you imagine might happen if this cranial nerve were damaged?
The cranial nerve is an extension of the brain that consists of 12 pairs of cranial nerves and is a component of the peripheral nervous system. Cranial nerves connect the brain to sensory receptors and effectors in the head, neck, and organs. It performs various functions, including those of a sensory, motor, and mixed nerve. The sensory nerve – the Olfactory, transports smell input from the nose, and the optic nerve – transports eye input.
As a motor nerve, the oculomotor nerve controls eye movements.
The facial nerve transports taste input from the tongue and control facial expression muscles as a mixed nerve.
If a person loses their cranial nerves, it can affect their sensory and motor functions. When a person’s oculomotor nerves are damaged, they cannot control their eye movement.
Imagine you have been hired by a pharmaceutical company to develop a drug to regulate a specific brain disorder. What is a major physiological roadblock to developing such a drug? How can you design a drug to bypass that roadblock so that the drug can be delivered to the brain where it is needed?
You’ll need to create a drug that can cross the blood-brain barrier (BBB). The medication should be either lipid- or water-soluble. The drug would be more likely to pass through the BBB if it could open a gap between the tight junctions of the endothelial cells of the brain capillaries. Targeting the drug to enter the brain in specific areas near the third ventricle (the circumventricular organs) may be an option because the BBB is absent in those areas, and the capillary endothelium is more permeable, allowing the blood-borne drug to enter brain tissue more easily.
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