XI Chap 21 Neural Control & Coordination Flashcards
________________ is the process through which 2 or more organs interact and complement the functions of one another
Coordination
Physical exercises is an example of coordination. T or F?
True
Functions of muscles, lungs, heart, blood vessels, kidney and other organs are coordinated while performing physical activity. T or F?
True
The __________ system and the __________ system jointly coordinate and integrate all activities of the organs.
neural, endocrine
Neural system provides an organised network of __________ for quick coordination
point-to-point connections
Endocrine system provides chemical integration through __________
hormones
Neural system of ALL animals is composed of neurons. T or F?
True
__________ are highly specialised cells which can detect, receive and transmit different kinds of stimuli.
Neurons
Neural organisation is very __________ (simple / complex) in lower invertebrates.
very simple
In Hydra, neural system is composed of __________
a network of neurons
Neural system is better organised in insects than lower invertebrates, where a __________ is present along with __________ and __________
brain, ganglia, neural tissues
Human neural system is divided into 2 parts:
CNS (central)
PNS (peripheral)
CNS includes the __________ and the __________
brain, spinal cord
CNS is the site of __________
information processing and control
PNS comprises of ALL the nerves in the body associated with CNS. T or F?
True
Nerve fibres of PNS are of 2 types:
afferent, efferent
Afferent vs efferent fibres
Afferent - impluses from tissues/organs to CNS
Efferent - regulatory impulses from CNS to peripheral tissues/organs
PNS is divided into 2 divisions:
somatic neural system
autonomic neural system
Somatic neural system vs Autonomic neural system?
Somatic - relays impulses from CNS to skeletal muscles
Autonomic - impulses from CNS to involuntary organs and smooth muscles
Autonomic neural system is further classified into:
sympathetic neural system
parasympathetic neural system
Visceral nervous system is part of __________ nervous system (central / peripheral)
peripheral
Visceral nervous system comprises of:
the whole complex of nerves, fibres, ganglia and plexuses by which impulses travel from CNS to viscera and from viscera to CNS
Neuron is a microscopic structure composed of 3 parts:
cell body, dendrites, axon
Cell body of neuron contains cytoplasm with __________ and certain granular bodies called __________
typical cell organelles, Nissl’s granules
Dendrites?
Short fibres
branch repeatedly
project out of cell body
also contain Nissl’s granules
Dendrite fibres transmit impulses towards the __________
cell body
Axon?
long fibre,
distal end of which is branched
Each axon terminates as a ____-like structure called __________ which posesses __________
bulb, synaptic knob, neurotransmitters
Neurotransmitters?
Synaptic vesicles containing chemicals at terminal end of axon
Axons transmit nerve impulses __________ (toward/away) from cell body
to a __________ or __________
away,
synapse,
neuro-muscular junction
Based on the number of axon and dendrites, neurons are divided into _____ (how many?) types. They are:
3;
multipolar - 1 axon, >=2 dendrites - found in cerebral cortex
bipolar - 1 axon, 1 dendrite - found in retina of eye
unipolar - 1 axon only - found in embryonic stage
There are 2 types of axons:
Explain
myelinated - enveloped which Schwann cells which form a myelin sheath
Non-myelinated - enclosed by Schwann cell that does NOT form a myelin sheath
Gaps between 2 adjacent myelin sheaths are called __________
nodes of Ranvier
Myelinated nerve fibres are found in __________ and __________ nerves
spinal, cranial
Unmyelinated nerve fibres are commonly found in __________ and __________
autonomous and somatic neural systems
Neurons are excitable cells because __________
their membranes are in a polarised state
Different types of ion channels are present on the neural membrane that are selectively permeable to different ions. T or F?
True
When a neuron is not conducting any impulse it is __________
resting
Axonal membrane of neuron is more permeable to __________ ions and nearly impermeable to __________ ions
K+, Na+
Axonal membrane is impermeable to __________
negatively charged proteins present in the axoplasm
The axoplasm inside the axon contains high concentration of __________ and low concentration of __________
high - K+, negatively charged proteins
low - Na+
The fluid outside the axon contains high concentration of __________ and low concentration of __________
high - Na+
low - K+
The ionic gradients across the resting axonal membrane are maintained by __________
active transport of ions / sodium - potassium pump
Sodium-potassium pump transports __________ outwards for __________ into the cell
3 Na+
2K+
Outer surface of the membrane possesses a __________ charge while the inner surface possesses a __________ charge and therefore is polarised.
positive, negative
What is resting potential?
Electrical potential difference across the resting plasma membrane of axon
When a stimulus is applied at a site A, it becomes freely permeable to ______ which leads to a rapid influx of _____
Na+, Na+
With influx of Na+ polarity at site on an axon is reversed i.e. outer surface is __________ charged and inner side becomes __________ charged
negatively, positively
When polarity of the axonal membrane is reversed it is known as __________
depolarised
Define action potential / nerve impulse
Electrical potential difference across the plasma membrane at site where stimulus is applied, Na+ influx and depolarisation occurs
At site of stimulus (say “A”), current flows on inner surface from __________ to __________ and on outer surface from __________ to __________
(say site immediately ahead is “B”)
inner: A to B
outer: B to A
Stimulus-induced permeability to Na+ is extremely __________ (permanent / short-lived)
short-lived
Stimulus-induced permeability to Na+ is quickly followed by rise in permeability to __________
K+
Within fraction of a second, K+ diffuses __________ (inside/outside) the membrane and restores the resting potential at the site of excitation
outside
A nerve impulse is transmitted from one neuron to another through junctions called __________
synapses
A synapse is formed by the membranes of __________ and __________
pre-synaptic neuron
post-synaptic neuron
Pre- and post-synaptic neurons are always separated by a gap called synaptic cleft. T or F?
False, may or may not be separated by synaptic cleft
What are the 2 types of synapses?
- electrical
2. chemical
Electrical vs. chemical synapse?
- Membranes of pre- and post are in very close proximity in electrical; separated by fluid-filled synaptic cleft in chemical
- current flows directly from one neuron to another (similar to impulse conduction along single axon); chemicals called neurotransmitters involved in impulse transmission
- electrical impulse transmission is faster than chemical
- electrical synapses are rare-r in our system than chemical
Axon terminals contain vesicles filled with __________
neurotransmitters
In a chemical synapse:
When an impulse arrives at axon terminal, it stimulates…
movement of synaptic vesicles towards membrane => vesicles fuse with plasma membrane => release neurotransmitters into synaptic cleft => neurotransmitters bind to specific receptors on post-synaptic membrane => ion channels open => generate new potential in post-synaptic neuron
New potential developed in a chemical synapse may be __________ or __________
excitory, inhibitory
__________ is the central information processing organ of our body and acts as the ‘command and control system’
brain
Brain controls:
voluntary movements, balance, functioning of vital involuntary organs (lungs/hearts/kidneys) thermoregulation hunger and thirst circadian (24-hour) rhythms, activities of several endocrine glands, human behaviour, processing of vision, hearing, speech, memory, intelligence, emotions and thoughts
Inside skull, brain is covered by __________
cranial meninges
Cranial meninges consist of 3 layers:
outer layer - dura mater
middle layer - arachnoid (very thin)
inner - pia mater (in contact with brain tissue)
Brain can be divided into 3 major parts:
forebrain,
midbrain,
hindbrain
Forebrain consists of __________ , __________ and __________
cerebrum, thalamus, hypothalamus
__________ forms the major part of the human brain
Cerebrum
A __________ divides the cerebrum longitudinally into 2 haves termed as __________ and __________
deep cleft, left and right cerebral hemispheres
The cerebral hemispheres are connected by a tract of nerve fibres called __________
corpus callosum
Layer of cells which covers the cerebral hemisphere is called __________ and is thrown into __________
cerebral cortex, prominent folds
Cerebral cortex is referred to as __________
grey matter (due to greyish appearance)