Week 1: Introduction to the Nervous System Flashcards
What is the nervous system?
The command centre of your body
What is included in the Nervous System?
Brain
Spinal Cord
Peripheral Nerves
What does the Nervous System do?
- Controls movement
- Generates thought
- Responds to stimuli
- Automatic responses
- Glands & hormone secretion
- Heart, digestion & breathing
How are stimulus used in the nervous system?
- Stimuli is transmitted through to the nervous system via a receptor
- The receptor converts the stimuli to a signal that the nervous system can understand
What are the main integration areas?
The brain and spinal cord
What is the role of chemoreceptors
Chemoreceptors sense the various concentrations of chemicals in the blood and sends this to the integration system which processes the information and then sends a signal for the glands to secrete or not secrete various hormones
Glands that can secrete hormones….
Pancreas: secretes hormones in response to blood sugar level changes
Adrenal glands: regulars salt and water balance. Also helps trigger the flight or fight response.
Pineal glands: regulates the sleep/wake cycle
Parathyroids: regulars level of calcium in the blood
What controls the pituitary gland?
The hypothalamus (located in the brain)
What is homeostasis?
A self-regulating process by which biological systems maintain stability while adjusting to external conditions
What is thermoregulatory control?
The control of temperature in the body
How does temperature control work with regards to homeostasis?
- Thermal input is provided from structures eg skin, deep tissue & spinal cord
- Signals are sent to and integrated by areas in the spinal cord and brain (hypothalamus)
- If temp increases above 37 degrees: sweating & vasodilation will occur. If temp decreases below 37 degrees: vasoconstriction and shivering will occur
Types of receptors…. (5)
Mechanoreceptors respond to physical force such as pressure, touch or muscle stretch/loading
Photoreceptors respond to light
Thermoreceptors respond to internal an external temperature changes
Nociceptors respond to a variety of stimuli associated with tissue damage
Chemoreceptors respond to dissolved chemicals during the sensation of taste and smell.
What are the two parts of the nervous system?
Central nervous system & Peripheral nervous system
What is included in the CNS
Brain & Spinal cord
The brain and spinal cord aren’t directly in contact with the bones that encase them…. T or F?
True
What protects the brain and spinal cord?
Meninges
What are the three layers of the meninges known as?
Pia matter (inner)
Arachnoid (middle)
Dura matter (outer)
Where is the brain located?
Encased in the skull within the cranial cavity
Role of the brain?
- Receives sensory information
- Integrates information from the PNS & spinal cord
- Contains control centres that assist with all body functions eg breathing, hormone release, etc
- Stores information
- Initiates responses
- Generates thoughts and emotions
What is the role of the spinal cord?
Relays signals from periphery to brain and from the brain to the periphery.
Also relays/integrates reflexes
Where is the spine located?
Travels from the back of the brain down the centre of the spine to the lumbar region
*Spinal cord = encased in the vertebrae.
How are motor and sensory nerves connected to the central nervous system?
Synapses
Allow for communication of information from the peripheral nerve endings to the CNS and the CNS to the peripheral nerves.
What two types of nerves exist within the peripheral nervous system?
Motor & sensory division
What is the motor division?
Transits signals (action potentials) from the CNS to organs, muscles, limbs and skin
What is the sensory division?
Transmits action potentials from sensory receptors to the CNS
What are the two elements of the peripheral nervous system?
Somatic nervous system & Autonomic nervous system
What two components make up the somatic nervous system?
Cranial nerves & Spinal nerves
What two components make up the autonomic nervous system?
Parasympathetic nervous system & sympathetic nervous system
Role of the somatic nervous system?
Produces voluntary movements (voluntary nervous system) and processes sensory information. It connects the CNS to skeletal muscles.
How many pairs of cranial nerves and spinal nerves are there?
12 cranial nerves & 31 spinal nerves
Do cranial nerves synapse directly with the brain?
Yes
*Spinal cords synapse directly with the spinal cord as well.
What are the types of nerves that makeup the somatic system?
Afferent & efferent nerves
Afferent vs efferent nerves?
Afferent nerves send information to the brain and spinal cord. These contain sensory neurons that inform the CNS about the things we sense eg touch, see, etc.
Efferent nerves send information from the brain and spinal cord to the periphery. These contain motor neurons responsible for voluntary movement.
What do cranial nerves do?
Relay information to and from regions of the head & neck including the special senses of vision, taste, smell & hearing
What is the breakdown of the 31 spinal nerves?
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
What is the autonomic nervous system?
Involuntary nervous system. Controls automatic processes. Largely related to the function of internal organs eg blood vessels, stomach, heart, etc.
Regulates digestion, heart rate, blood pressure, balance of water and electrolytes etc (not controlled consciously)
Sympathetic vs parasympathetic systems
After the autonomic nervous system receives information about the body and its internal and external environment, the stimulation of the processes usually occurs through the sympathetic division and the inhibition of these processes usually occurs through the parasympathetic
How many nerve cells are involved in the autonomic pathway and where are these located?
Two nerve cells. One located in the brain stem or the spinal cord which is connected to fibres of another nerve cell. This is located in a cluster of nerve cells known as an autonomic ganglion.
What do the nerve fibres from the ganglia connect with?
Internal organs
4 key features of sympathetic nervous system
- Active during physical activity
- Increases energy usage
- Increases arousal
- FIGHT OR FLIGHT RESPONSES
*IE it is engaged when you are stressed - accelerates HR, widens the bronchiole passages, decreases mobility in the large intestine, constricts blood vessels to the periphery and dilates blood vessels, causes pupil dilation and causes you to start sweating as well as raising your blood pressure.
4 key features of parasympathetic nervous system?
- Conserves energy
- Regulates resting functions
- Reduces arousal
- REST AND DIGEST RESPONSES
In order to conserve energy it slows the HR, relaxes the muscles of the gastrointestinal and urinary tract and increase intestinal and gland activity.
