Nervous System- Exam Bs Flashcards
What are antibiotics?
Drugs that for that infection against bacteria.
Bactericidal antibiotics- kill bacteria by changing the structure of the cell, wall or cell membrane , or by distrusting the action of essential enzymes
Eg. Penicillin
Bacteriostatic antibiotics- stop bacteria from reproducing, usually by distrusting protein synthesis, preventing metabolic process ie. cell respiration, altering nucleus acid
Eg. Tetracycline
What antivirals?
Drugs that work against viral infections. They inhibit the development of viruses (inactivate). Viral proteins are disabled by specifically designed chemicals. Preventing viruses from entering cells, synthesis of viral genome and prevent release of virus.
Eg. Inferferons
What is homeostasis?
Maintainance of a constant internal environment
Eg. Temperature, body fluids, ion concentration, glucose and blood pressure
What are the components of a feedback loop?
Stimulus Receptor Modulator Effector Response Feedback (pos or neg)
What are the 6 types of receptors?
Thermoreceptors- heat and cold
Osmoreceptors- detect change in osmotic pressure
Chemoreceptors- detect change in blood oxygen and carbon dioxide
Pressoreceptors- detect change in blood pressure changes (skin)
Baroreceptors- detect changes in blood pressure
Nocireceptor- respond to damaging or potentially damaging stimuli, pain receptor
Nature of message in nervous system and endocrine system?
N system- electrical impulses and neurotransmitters
E system- hormones
Transport of message in nervous system and endocrine system?
N system- along membrane of neuron
E system- by the bloodstream
Cells affected in nervous system and endocrine system?
N system- muscles and gland cells; other neurons
E system- all body cells
Types of response by nervous system and endocrine system?
N system - usually local and specific
E system- may be general and widespread
Time taken to respond with nervous system compared endocrine system?
N system- rapid ( within milliseconds)
E system- slower ( seconds to days)
Duration of nervous system and endocrine system responses?
N system- brief ( stops quickly when stimulus stops)
E system - longer lasting ( may continue long after the stimulus has stopped)
What are reflexs?
Rapid and autonomic responses to a change in the environment. They are coordinated by the spinal cord on an involuntary bandits. Once the reflex has occurred, an impulse is sent to the brain and the person becomes aware of the situation.
4 important properties of reflexes?
- Stimulus
- Involuntary and rapid
- Small no. Of neurons involved
- Stereotyped (same way each time)
What route does the reflex arc take?
- Sensory receptor detects stimulus and generates nerve impulse in a sensory neuron (pain= nociceptor)
- Sensory neuron carries impulse into the spinal cord via the dorsal root ganglion and Dordal root
- Impulse transmitted into an interneuron in the grey matter of spinal cord
- Interneuron transmits impulse to a motor neuron. Motor neuron carries impulse out via the ventral root to the effector.
- Effector responds to remove the stimulus
- While reflex is being carried out, an impulse is sent to the brain so an individual becomes aware of the situation. Upper sensory neuron carries the message.
What is the hole in the middle of the spinal column grey matter called?
Central canal
What is the dorsal route ganglion?
A group of cell bodies ( somas)
What are protective reflexes?
- born with them Eg. Sneezing, coughing, blinking
- protect the body from injury
- up spinal cord only
What are acquired reflexesa.
- reflexes learnt through constant repetition.
Eg, maintenance of balance while riding a bike, jamming brakes on car to avoid dangerous situations or flinching when ball is coming
What is the nervous system?
Communication network and control center of body. It is involved in maintenance of homeostasis inside the body, a task it shares with the endocrine system
What is the central nervous system?
Control centre consisting of brain and spinal cord
What is the peripheral nervous system?
Nerves that connect central nervous system with the receptors, muscles and glands
What are neurons?
Nerve cells which are the basic structural and functional units of whole nervous system
What is myeline sheath?
Layer of fatty material that covers axons and increases speed of nerve impulse.
What is an axon?
Long extension of nerve fibres from cell body
What are dendrites?
Short extension of cytoplasm of cell body. They Often have many branches, receive messages from other neurons and carry them towards the cell body.
What is the cell body?
Soma: contains nucleus and many other organelles
What is node of Ranvier?
Interval of gaps along the axon
What are schwann cells?
The cell that wraps around a nerve fibre forming the myelin sheath
What shoe of neurons are receptors found on?
Sensory only
Functional neurons?
Sensory, motor and inter neurons
What are sensory neurons?
Receptor neurons that carry messages from receptors in the sense organs or skin to the CNS
What are motor neurons?
Neurons that carry messages from CNS to the muscles and glands- the effectors
What are interneurons?
Association, relay or connector neurons located in the CNS and are links between sensory and motor neurons
What are the structural neuron types?
Multipolar- 1 axon, multiple dendrites
Bipolar- 1 axon and 1 dendrite
Unipolar- 1 axon extension and cell body to one side of it.
What is a nerve fibre?
Any long extension of cytoplasm for a nerve cell body
What is a nerve?
Bundle of nerve fibre held together by connective tissue
What is a synapse?
Junction between branches of adjacent neurons. Messages are passed across the synapse.
What are nerve impulses?
-Electrochemical charge that travels along nerve fibre.
Where does a Nerve impulse start?
The dendrite
How does nerve impulse generation start? (Breif)
- Resting neuron contains POTENTIAL ENERGY. This comes from the difference between the electrical charge on the inside and outside of a neuron.
- Nerve impulse = ACTION POTENTIAL
A change in the EXtracellular fluid and intracellular fluid generates an impulse that propagates ( moves) along neuron.
~The nerve impulse undergoes polarisation, depolarisation, repolarisation, and hyperpolarisation~
What happens at the polarisation stage of nerve impulse generation?
there is a positive EF (due to sodium) &a negative IF (due to large - proteins).
RESTING MEMBRANE POTENTIAL= -70mv
potassium readily diffuses through cell membrane into EF. The Na/ K pump actively pumps potassium back into cell.
What happens at depolarisation of nerve impulse generation?
- a stimulus opens some Na+ voltage gated channels and Na+ moves into cell causing cell to become positive .
- when membrane potential reaches -55mv an all or none response occurs
- all Na+ voltage channels open in that area causing an influx of Na+ = positive IF