Nervous System Flashcards
Briefly describe the role of the nervous system in the body
The nervous system is responsible for all behaviours, memories and movements
The nervous system helps to maintain homeostasis.
What are the 2 structural divisions of the nervous system?
Central nervous system (CNS), Peripheral nervous system (PNS)
What does the Peripheral nervous system (PNS) control.
cranial nerves (12 pairs), spinal nerves (31 pairs)
What does the Central nervous system (CNS) control.
brain and spinal cord
What are the 2 main types of cell in the nervous and their functions.
Neurons (nerve cells) • conduct nerve impulses • analyse information, store memories, direct the body’s responses Neuroglia • Support, nurture, protect neurons
What is a dentrite
receive information from the environment and from other neurons and carry electrical signals towards the cell body
What is a cell body
integrates incoming signals and initiates a nerve impulse or inhibits sending a nerve impulse
What is an Axon
conducts nerve impulses away from cell body to the axon terminals
What is a Myelin Sheath
insulates sections of the axon and speeds up conduction of nerve impulses
What is Axon terminals
release a neurotransmitter onto another neuron, a muscle or a glands
What are the three types of nuerons
Sensory, Interneurons, motor neurons
What are 2 types of Peripheral NS
Somatic and autonomic
What is Somatic NS
• conveying sensory information from somatic receptors in the head, body wall, limbs and from the senses (vision, hearing, smell, taste…) to the CNS
• conducting impulses from CNS to skeletal muscles only
voluntary actions / consciously controlled responses
What is Autonomic NS
- conveying sensory information from receptors in the visceral organs
- conducting impulses from CNS to cardiac muscle, smooth muscle and glands
- involuntary actions / subconsciously controlled responses
What are the Autonomic NS divisions
Sympathetic nervous system, Parasympathetic nervous system
What is Parasympathetic nervous system.
- prepares the body for rest, recovery, healing
- directs what are referred to as our ‘rest and digest’ responses
- increases the number of impulses sent to the digestive system (↑ the rate of digestion) so the body can replenish it’s energy supplies, heal damaged tissues, and so on
What is the sympathetic NS
Prepares the body to deal with ‘E’ situations
(e.g. emergencies, exercise, energy expenditure)
• directs what are referred to as ‘fight or flight’ responses
• increases the number of impulses sent to the heart (↑ heart rate), skeletal muscle blood vessels (vasodilate to allow ↑ glucose and O2 to muscles)
What is the Neuromuscular Junction Function
• Nerve cells are separated from one another or from a muscle fibre by a minute gap (or space) called a synapse.
• To continue the transmission of a nerve impulse in another neuron, or to activate a muscle, a nerve impulse must cross the synapse (the gap).
• It does this with the aid of chemical neurotransmitters secreted at the ends of the axon.
Calcium is also required.
What is the Neuromuscular Junction process
- Impulse arrives at axon terminal
- Neurotransmitter (NT) is released from secretory vesicles
- NT crosses gap/synapse to receptors on muscle fibre
- Muscle fibre is stimulated to contract
- NT is recycled back into axon terminal
What is the function of Sensory function (PNS)
to sense changes in the internal and external environment (stimuli) through sensory receptors and relay the information to the CNS
What is the function of Integrative function (CNS)
to analyze the sensory information, store some aspects and make decisions regarding appropriate responses
What is the function of Motor function (PNS)
to respond to stimuli by initiating action in effectors
What are the five structures always involved in a change
Receptors, sensory neurons, CNS, Motor neurons, effectors
What is a reflex
A reflex is a rapid, predictable sequence of involuntary actions that occur in response to a particular stimulus
list the components in a Somatic nervous system reflex.
For example: the patellar tendon reflex
receptors - detect stimulus (rapid stretch of quadriceps muscle)
sensory neurons - carry impulses from receptors → CNS
CNS – impulses are ‘processed/interpreted’ in the CNS (spinal cord)
motor neurons - carry impulses from CNS → effector (quadriceps muscle)
effectors – carry out appropriate response (quadriceps muscle contracts and prevents any further stretch)
What is the cerebrum
- Has many convolutions which effectively triple its surface area
- Makes up 40% of total brain mass
- Contains billions of neurons
What is the cerebellum
• Highly folded surface
What is the brain steam
• Connects to the spinal cord
What is the cerebrum functions
- Sensory awareness
- Initiates voluntary (conscious) motor activities
- Analyses information for thinking, learning ..
- Stores memories
What is the cerebellum functions
- Provides smooth, co-ordinated skeletal muscle movements
* Regulates posture and maintains balance subconsciously
What is the brain steam functions
• Has centres for control of basic activities for survival o cardiac (heartbeat), respiratory (breathing) and vasomotor (blood vessel diameter)
What are the lobes of the cerebrum.
frontal, parietal, occipital, temporal
What is the function of meninges
The brain is surrounded by layers of membrane called meninges
Between the layers nearest the brain is a clear, watery fluid called cerebrospinal fluid (CSF)
CSF provides physical and chemical protection of the brain
Give an example of an infection in the nervous system.
• Meningitis - Infection and inflammation of the meninges
Name a bacterial, viral and fungal infection of the nervous stystem
Tetanus (Clostridium tetani), Viral meningitis, Fungal meningitis
How do microbes gain access to the nervous system
Nasal colonisation, invasion of blood stream, damage to the meninges
What is the Link between nervous and endocrine systems
The hypothalamus is a major link between nervous and endocrine systems
The hypothalamus is a small region deep in the brain.
