Homeostasis
The maintenance of a stable internal environment in the body
homeostasis
This detects the stimulus
receptor
These structures widen during vasodilation
blood vessels
The two types of feedback in homeostasis are:
negative and positive
Rapid muscle contractions that generate heat are known as:
shivering
The long section of a neuron
axon
This is the tiny gap between two neurons.
synapse
Chemical messengers of the endocrine system
hormones
This organ system uses electrical signals to help maintain internal balance.
nervous system
A change detected by the body is called a
stimulus
These structures are activated to increase evaporation from the skin
sweat glands
When the body corrects a change by reversing it—such as lowering high temperature—it is using this type of feedback.
negative
When skin blood vessels widen to increase heat loss from the skin.
vasodilation
These neurons carry information from receptors to the CNS.
sensory neurons
This structure insulates the axon and helps speed up the nerve impulse
myelin sheath
Hormones bind to these on target cells
receptors
This organ system uses hormones to help maintain internal balance.
endocrine system
Compares conditions to the set point and sends signals to the effectors
control centre
Specialised tissue that is densely packed with mitochondria for generating heat
When you cut yourself, platelets sticking to the wound trigger chemicals that attract even more platelets to seal the injury. Is this negative or positive feedback?
positive feedback
When skin blood vessels narrow to reduce heat loss from the skin.
vasoconstriction
These neurons carry commands from the CNS to muscles or glands.
motor neurons
These chemicals carry messages across a synapse.
neurotransmitters
During upregulation, a cell becomes _______ sensitive to a hormone
more
The ideal target value for a variable
set point
Muscles or glands that act to correct the change are known as
effectors
Gland in the brain that regulates many body processes including temperature.
hypothalamus
When CO₂ levels in the blood rise, this triggers faster, deeper breathing to remove more CO₂, bringing levels back down. Is this an example of negative or positive feedback?
negative feedback
Control centre in the thermoregulation feedback loop
hypothalamus
The 'branches' at the top of the neuron
dendrites
This structure releases neurotransmitters into the synapse.
axon terminal
When a cell reduces the number of surface receptors it displays so it is less sensitive to a hormone, this is called
downregulation
Outside of this range, organisms cannot survive
tolerance limits
Contrast the nervous and endocrine systems in terms of method and speed of communication.
Nervous uses electrical signals, endocrine uses hormones
Nervous is faster, endocrine slower and longer lasting
These structures detect changes in pH in the blood
chemoreceptors
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?
positive feedback
Special group of neurons in the hypothalamus that monitor blood temperature directly.
thermoreceptors
Arrange these in the correct order for a nervous system response to stimulus: motor neuron, sensory neuron, receptor, effector, interneuron.
Stimulus → _________ → .....
receptor → sensory neuron → interneuron → motor neuron → effector
The process in which a signal is converted from electrical to chemical and back to electrical
signal transduction
Researchers observe that cells exposed to low concentrations of a hormone for several weeks become increasingly sensitive to that hormone despite its concentration remaining low. What cellular process is likely to have caused this increase in sensitivity?
upregulation