Chapter 13 - Neuronal Communication Flashcards
What is the stimulus of sight?
Light
What type of receptors are involved in sight?
Photoreceptors
Example of places where photoreceptors are found
Rods and cones
What is the stimulus of smell?
Chemicals
What type of receptors are involved in smell?
Chemoreceptors
Example of place where chemoreceptors are found
Nose
Tongue
What is the stimulus of hearing?
Sound waves
What type of receptors are involved in hearing?
Mechanoreceptors
Example of places where mechanoreceptors are found
Cochlea
Skin
What is the stimulus of touch?
Pressure
What type of receptors are involved in touch?
Mechanoreceptors
What is the stimulus of taste?
Chemicals
What type of receptors are involved in taste?
Chemoreceptors
What do thermoreceptors respond to?
Heat
Where is the node of ravier?
The gap between myelin sheaths along the axon
Where is myelin sheaths found?
Around the axon
What do myelin sheaths do?
Act insulation for the axon, meaning electrical impulses cannot escape and increasing the speed of transmission
What is effect of greater axon diameter on speed of conduction/transmission?
A greater axon diameter = a faster speed of transmission of electrical impulses
3 examples of internal environments
Cell pH
Internal temperature
Blood glucose concentration
3 examples of external environments
Light intensity
External temperature
Sudden pressure
What two ways do animals react to environmental changes?
Through electrical impulses (via neurones)
Through chemical responses (via hormones)
How do plants react to environmental changes?
Through a variety of different chemical communication/response systems
What is homeostasis?
The tendency to maintain a stable, relatively constant internal environment within the body
How do nervous and hormonal systems coordinate activity on a cellular level?
Through cell signalling
What is cell signalling?
Where a cell releases a chemical which has an effect on another cell
What is the cell that responds to a cell signal called?
The target cell
Example of local cell signalling
Between neurones at synapses
How are cell signals transmitted over long distances?
Through the use of hormones
Example of long distance cell signalling
Pituitary gland secretes ADH which acts of cells in the kidney to control water levels
Do plants have a nervous system?
No. Instead they rely on hormones in coordinating responses to environmental changes
What makes up your CNS?
Your brain and spinal cord
What makes up your PNS?
All the neurones that connect the CNS to the rest of the body. This includes the sensory and motor neurones
What are the two functionally organised systems that make up nervous system?
The somatic nervous system
The autonomic nervous system
What are the two structurally organised systems that make up the nervous system?
The CNS and the PNS
What is the somatic nervous system?
The system that is under conscious control i.e. it is used when you do something voluntarily e.g. when you more a muscle in your arm
What is the autonomic nervous system?
The system that is under subconscious control i.e. when your body does something automatic and involuntary e.g. your heart beating
What is the autonomic nervous system further divided into?
The sympathetic and parasympathetic nervous systems
What is the sympathetic nervous system associated with?
Fight or flight
What is the parasympathetic nervous system associated with?
Rest and digest
What does the sympathetic nervous system do?
Increases things like heart and respiratory rate, and releases stored glucose (energy), while inhibiting less important processes like digestion
What does the parasympathetic nervous system do?
Decreases things like heart and respiratory rate, and increases processes like digestion and energy storage
What is the brain responsible for?
- Processing all information collected by receptor cells
- Receiving and processing information from the hormonal system
What is the advantage of having a single central control centre for the whole body (the brain)?
Communication between the billions of neurones involved is much faster than if there were control centres for different functions
What reaction does the brain not process?
Reflex reactions
What are meninges?
The protective membrane around the brain
What are the 5 main areas of the brain?
- Cerebrum
- Cerebellum
- Medulla oblongata
- Hypothalamus
- Pituitary gland
What is the function of the cerebrum?
Controls voluntary actions, such as learning, memory, personality and conscious thought
What is the function of the cerebellum?
Controls unconscious functions, such as posture and balance
What is the function of the medulla oblongata?
Used in control of the autonomic nervous system, such as for controlling heart rate and breathing rate
What is the function of the hypothalamus?
The regulatory centre for temperature and water balance
What is the function of the pituitary gland?
Stores and secretes hormones that regulate many body functions
How does the cerebrum work?
It receives sensory information, interprets it and then sends impulses along motor neurones to effectors to produce an appropriate response
What is the effect of the cerebrum being highly convoluted?
It increases its surface area significantly, increases its capacity for complex activity
What is the cerebrum split it up into?
It is split into left and right halves known as cerebral hemispheres
What is the significance of the different cerebral hemispheres?
Each hemisphere controls one half of the body, and has discrete areas which perform specific areas. These areas are mirrored in both halves
What is the cerebral cortex?
The 2-4mm thick outer layer of the brain
Where do the most sophisticated processes occur in the brain?
The frontal and prefrontal lobe
Where does the left hemisphere receive impulses from?
From the right hand side of the body
Where does the right hemisphere receive impulses from?
From the left hand side of the body
What do sensory areas of the brain do?
Receive information about from receptor cells
What do association areas of the brain do?
Information is analysed and then acted upon
Does the cerebellum initiate movement?
No, it rather controls movement
What may be one effect of a damaged cerebellum?
Jerky uncoordinated movement
How many centres does the hypothalamus have?
2- one for the parasympathetic and one for the sympathetic nervous system
What are 3 roles of the hypolthalamus?
- Controlling complex patterns of behaviour e.g. sleeping and feeding
- Monitoring the composition of blood plasma, such as the concentration of blood glucose + water
- Producing hormones
Where is the pituitary gland found?
The base of the hypothalamus
What is the pituitary gland split up into?
The anterior (front) and posterior (back) pituitary
What does the anterior pituitary do?
Produces 6 hormones, such as FSH (which is used in reproduction and growth hormones)
What does the posterior pituitary do?
Stores and releases hormones produced by hypothalamus
What is the main difference between normal actions and reflex actions?
Reflex actions do not involve conscious thought i.e. the nervous impulse does not travel to the brain; this allows for faster response times
Summarise the steps of a reflex reaction
Stimulus
Receptors
Sensory neurone sends impulses to the spinal cord
Relay neurone passes impulses through and back out of the spinal cord
Motor neurone sends impulses to muscles
Effector contracts
Give two common reflexes
Knee-jerk reflex
Blinking reflex
What acts as the stimulus of the knee-jerk reflex?
The stretching of patellar tendon
What is skeletal muscle?
Make up the bulk of the body muscle tissue. Responsible for movement
What is cardiac muscle?
Muscle found only in the heart. They are myogenic, meaning they contract without the need for nervous stimulus
What is involuntary muscle also known as?
Smooth muscle
What is smooth/involuntary muscle?
Muscle found in many parts of the body e.g. in the walls of the stomach
