Homeostasis and Feedback Loops
Homeostasis is
A state of equilibrium in the physical and chemical internal conditions of the body, maintained by the body systems.
This is the tiny gap between two neurons
Synapse
Rapid muscle contractions that generate heat are known as
Shivering
What two hormones are involved in the regulation of body fluids?
ADH and Aldosterone
Chemical messengers of the endocrine system are
Hormones
When the body corrects a change by reversing it - such as lowering high temperature - it is using what type of feedback
Negative
These neurons carry information from receptors to the CNS
Sensory Neurons
When skin blood vessels widen to increase heat loss from the skin
Vasodilation
What is the main organ responsible for osmoregulation in humans?
Kidneys
How do hormones travel around the body?
In the blood
What is the key difference between a positive and a negative feedback loop?
A negative feedback loop reverses the original stimulus to restore balance; a positive feedback loop amplifies the stimulus, pushing the system further from its starting point until something external stops it.
These chemicals carry messages across a synapse.
Neurotransmitters
Classification for an organism whose body temperature is dependent on its environment
Ectotherm
What is the functional/filtering unit of the kidney called?
The nephron
Where is ADH produced, and where is it released from?
ADH is produced in the hypothalamus and stored/released from the posterior pituitary gland.
During some infections, immune cells release chemicals called pyrogens that cause body temperature to rise. A higher temperature can stimulate immune activity, leading to the release of more pyrogens and a further increase in temperature until the infection is controlled. This is an example of which type of feedback?
These receptors allow you to taste and detect the food that you eat.
chemoreceptors
A physiological state of inactivity whereby the metabolic rate of an organism is lowered to save energy (typically lasts for a few hours).
Torpor
List the structural and and homeostatic mechanisms used to maintain water balance in plants and explain what they are
Structural - stomata (pores found on the underside of a leaf that allow transpiration), vacuole (large organelle in a plant cell that stores water), cuticles (protective, waxy coat on the outside layer of plant)
Homeostatic - abscisic acid (plant hormone that causes the stomata to close to prevent water loss)
Name the hormone that acts on the distal convoluted tubule (DCT) to increase sodium reabsorption, and state where it is released from.
Aldosterone, released from the adrenal cortex.
Put the following homeostasis features in order: control center, effector, stimulus, response, receptor
stimulus, receptor, control center, effector, response
List the main structural parts of a neuron.
Dendrites, body, soma, axon, myelin sheath, nodes of Ranvier, synapse and axon terminals.
Special group of neurons in the hypothalamus that monitor blood temperature directly
Thermoreceptors
Alcohol and caffeine are diuretic agents. Why would they then cause dehydration in the body?
They counteract the action of antidiuretic hormone. This makes the Distal Convoluted Tubule and Collecting Duct less permeable to water - meaning more is excreted through the kidney -- more lost as urine -- causing dehydration.
What effect does ADH have on the collecting duct of the nephron?
ADH increases the permeability of the collecting duct to water, increasing water reabsorption back into the blood and reducing urine output.