How is the short-term strength of the response controlled in the nervous system?
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By the frequency of impulses (action potentials) of nerve cells.
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How is the short-term strength of the response controlled in the nervous system?
By the frequency of impulses (action potentials) of nerve cells.
What do pancreatic beta cells sense in the extracellular fluid (ECF)?
Increased glucose concentration.
What is homeostasis?
Homeostasis is the process by which the body maintains a stable internal environment despite changes in external conditions.
What is the role of effectors in maintaining homeostasis?
Effectors bring about the desired change to maintain homeostasis.
What is the role of the urinary system?
To excrete urea and regulate water and salt balance.
What type of responses would you want to regulate with the nervous system and why?
Immediate and localized responses, because the nervous system provides fast and targeted signals.
What is the role of the circulatory system in homeostasis?
To transport O2, CO2, nutrients, and heat.
What are some examples of integrating centers in the body?
The brain and the pancreas.
How long do signals last in nervous regulation?
Signals are short-lived.
What are the two main components of extracellular fluid (ECF)?
Interstitial fluid and plasma.
What is the primary function of the extracellular fluid (ECF)?
To transport nutrients, oxygen, and waste products to and from cells.
What is the primary mechanism for maintaining homeostasis?
Negative feedback.
How do hormones travel through the body?
In the circulatory system.
What types of signals are involved in cellular communication for homeostatic regulation?
Chemical and electrical signals.
How is the movement of substances between intracellular fluid and interstitial fluid regulated?
The movement of substances between the intracellular fluid and the interstitial fluid is tightly regulated.
What is the size of the target in nervous regulation?
Very small, limited to a number of cells innervated.
What type of responses would you want to regulate with hormones and why?
Long-term and widespread responses, because hormones can affect many cells and have prolonged effects.
What are some environmental factors that a single-cell organism is directly exposed to?
Food source, temperature, pH, oxygen, and toxins.
What is the role of the respiratory system in homeostasis?
To exchange oxygen (O2) and carbon dioxide (CO2) with the environment.
How is the short-term strength of the response controlled in the endocrine system?
By the concentration of the circulating (and available) hormone.
What does homeostatic regulation involve?
Multiple organs and requires communication between cells, tissues, and organs. by hormones and nervous system
What is the role of receptors in maintaining homeostasis?
Receptors monitor homeostatic parameters such as glucose, heat, and oxygen.
What is the function of the integrating center in homeostasis?
The integrating center analyzes information from receptors and brings about the proper response.
What is the relationship between the compositions of interstitial fluid and plasma?
There is rapid equilibration of most substances between the interstitial fluid and the plasma, making their compositions very similar.
How is the activity of effectors turned off once homeostasis is restored?
Through negative feedback mechanisms. Response decreases stimulus, system shuts off
What is the environment in which the cells of a multicellular organism live?
Interstitial fluid.
What is the fluid inside cells called?
Intracellular fluid.
What are the main systems involved in communication within the body?
The endocrine system (hormone secreting gland cell), the nervous system (nerve cell), and the neuro-endocrine system (nerve cell).
How does information travel in nervous regulation?
By nerve cells to target organs such as muscles and glands.
What hormone is secreted by pancreatic beta cells in response to increased ECF glucose?
Insulin.
How fast is the response in nervous regulation?
Very fast, occurring in fractions of seconds.
What mechanisms does the body use to stop heat loss?
The body stops heat loss by constricting blood vessels (vasoconstriction), reducing sweat production, and increasing insulation through fat and clothing.
What is an example of an autocrine/paracrine agent that acts as a local vasodilator?
Nitric oxide.
What is the role of plasma in the extracellular fluid (ECF)?
To transport blood cells, nutrients, and waste products throughout the body.
Which tissues respond to insulin to take up glucose from the ECF?
Liver (store as glycogen), fat (adipose) (store as fat), and skeletal muscle (store as glycogen).
At what concentrations do hormones typically work?
Hormones work at very low concentrations, for example, plasma glucagon is approximately 50 x 10^-12 g/ml.
How fast is the response to hormones?
The response is slow, taking minutes to days.
What are the main fluid compartments in the human body?
Intracellular fluid (ICF) and extracellular fluid (ECF): interstitial fluid is 80% of ECF and plasma is 20% of ECF.
How are hormones removed from circulation?
Hormones are either inactivated by enzymes or excreted in urine.
Where are hormones produced?
Hormones are produced by endocrine glands, usually by cells specialized in producing a single hormone.
Do all cells respond to hormones?
No, all cells are exposed to hormones, but only those with receptors respond.
What is the role of interstitial fluid?
To surround and bathe the cells, providing a medium for nutrient and waste exchange.
What is a common waste product of cellular metabolism that must be removed?
Carbon dioxide (CO2).
What type of feedback mechanism is involved in blood glucose regulation?
Negative feedback.
What is the primary function of autocrine and paracrine regulation?
To provide local control within tissues or organs.
Which systems are involved in water and ion balance?
Digestive, urinary, and circulatory systems.
Which systems regulate the volume and pressure of bodily fluids?
Urinary and digestive systems.
What are the four components of all negative feedback systems?
Sensor (receptor), Set Point, Integrator, Effector.
How can a few hormone-producing cells control many cells?
A few hormone-producing cells can control many cells through the widespread distribution of hormones in the circulatory system.
What are neurosecretory neurons?
Neurons that secrete hormones.
How do autocrine and paracrine agents act?
They act only on neighboring cells and do not travel through the blood.
Which system is responsible for the absorption of nutrients like glucose and amino acids?
The digestive system.
What is the primary function of the intracellular fluid (ICF)?
To provide a medium for cellular processes.
Which systems are responsible for the exchange of O2 and CO2?
The respiratory and circulatory systems.
How do negative feedback systems help in temperature regulation?
They integrate responses to restore the body temperature to the set point.
What are the primary gases exchanged in the respiratory system?
Oxygen (O2) and carbon dioxide (CO2).
Which system is responsible for nutrient absorption?
Digestive system.
What percentage of total body water is contained within the intracellular fluid (ICF)?
Approximately 60%.
Which system is responsible for the distribution of heat, water, and salts throughout the body?
The circulatory system.
Where do we need to look to understand how cellular changes occur?
At the interface (cell membrane) between the cell and its environment (the interstitial fluid).
Which systems coordinate physiological changes among multiple organs and tissues?
The nervous and endocrine systems.
What role do hormones and neural signals play in cellular action?
They bring information to the surface of cells.
What systems are responsible for nutrient availability?
digestive and circulatory
What systems are responsible for regulating pH?
respiratory, urinary, circulatory
What systems are responsible for removing waste?
circulatory, respiratory, and urinary
How is blood glucose regulated?
eat meal, BG concentration increases, pancreas releases insulin, insulin affects target cells by taking up glucose to use for energy or storage, BG goes down and pancreas stops producing insulin
