The central nervous system Flashcards
1
Q
what is the CNS comprised of?
A
brain and spinal cord
2
Q
what protects the CNS?
A
bones
meniges
cerebrospinal fluid
3
Q
what is the function of the cerebrospinal fluid?
A
protects- being a shock absorber
supports - brain floats in it
transports- nutrition and waste
4
Q
what is the meninges comprise of?
A
Dura mater
Arachnoid mater
Pia mater
5
Q
what is the dura mater?
A
a thick durable layer attached to the skull
6
Q
What is the arachnoid mater?
A
attached to the dura mater to provide a cushion effect
7
Q
what is the Pia mater?
A
thin membrane that follows the gyri and sulci
8
Q
draw the diagram of the spinal cord ?
A
must include grey matter central canal which contain cerebrospinal fluid and white matter
9
Q
what is a ascending movement ?
A
a sensory axon that carry a nerve impulse towards the brain
10
Q
what is a descending movement?
A
motor axon that carry impulses away from the brain
11
Q
what are neurons?
A
highly specialised cells that carry’s information form one part of the body top another
12
Q
what do glial cells do ?
A
supports, protects, provides nutrition and insulates them from each other
13
Q
what is an afferent neuron?
A
takes nerve impulses from the receptors to the central nervous system
14
Q
what is an efferent neuron?
A
take nerve impulses from the central nervous system to the effector structure
15
Q
what is an interneuron?
A
they link sensory neurons and motor neurons together
16
Q
what are the four types of neuron ?
A
unipolar
bipolar
multipolar
pseudo-unipolar
17
Q
what is the structure of a unipolar neuron ?
A
has on extension from the cell body to the axon terminal
18
Q
what is the structure of a bipolar neuron ?
A
a distinct axon and have a dendritic fibre that is separated by a cell body
19
Q
what is the structure of a multipolar neuron ?
A
have a single axon and several dendritic fibres
20
Q
what is the structure of a pseudo-unipolar neuron ?
A
a single axon from a cell body which branches of into dendrites an axon terminals
21
Q
what are propertise and characteristics of a dendrite ?
A
short and highly branched
synapses with other neurons or receptors
transmit the electrochemical impulse towards the cell body
22
Q
what are propertise and characteristics of axon ?
A
Typically a single long nerve fibre
terminate at synaptic end bulbs
connects with muscles, glands and other neurons
23
Q
what is the myelin sheath ?
A
a fatty white sheath that surrounds the axon on most neurons
24
Q
what is the myelin sheath created by ?
A
schwann cells
25
what is a benefit of a neuron having a myelin sheath ?
transmission of nerve impulse occurs faster
26
what are the gaps between the sheaths called ?
the node of ranvier
27
what is a reflex ?
a rapid automatic response to a change in the internal and/or external environment
28
What is a spinal reflex ?
a reflex carried out by the spinal cord the message is not sent to the brain until after response meaning it is involuntary.
29
What is a reflex arc ?
-receptor detects a stimulus
-sensory neuron sends a message to the central nervous system
-message is passed on to either a motor neuron or interneuron
-motor neuron sends message to the effector
-effector carries out a response
- message is sent to the brain
30
what are the two types of relfex?
Innate
Acquired
31
what is an innate reflex?
a relex that is built in as apart of being a human eg suckling grasping
32
What is a acquire reflex?
a reflex that is learnt eg catching a ball
33
Describe the process of action potential ?
1. Stimulus is applied – membrane becomes permeable and sodium moves into the cell causing depolarisation: an all or none response occurs if decrease is more than a 15mV (threshold) so more sodium ions are allowed into the cell
2. Depolarisation – when action potential is created from sodium ions allowed into the cell
3. Repolarisation – ion channels on the inside of the membrane allow potassium ions out: this restores the electrical balance
4. Hyperpolarisation – returning to the resting membrane
potential there is more potassium on the outside than
sodium on inside: causes membrane potential to drop and then returns to normal state
5. 1-4 steps refractory period – the brief time during and after-action potential when the neuron cannot be stimulated
34
what is a saltatory conduction?
the process of nerve impulse moving down the myelinated axon by jumping from one node of ranvier to the next
35
Describe the process of transmission across a synapse?
1. Membrane depolarises – the end of an axon, calcium gates will open, letting calcium ions enter the cell
2. Synaptic vesicle release neurotransmitters – relay message between neurons
3. Neurotransmitters bind with receptors – bind on the neuron (acetylcholine, dopamine, adrenaline)
4. Excitation or inhibition – occurs depending on the neurotransmitter
* Excitation – sending message – nerve impulse is generated when sodium enters the cell and depolarisation occurs
* Inhibition – nerve impulse is not sent because potassium moves out of cell: hyperpolarisation is reached
36
What is the definition of homeostasis ?
the process by which the bodys internal environment is maintained at a steady state.
37
Define the term stimulus ?
a change in the internal and external environment
38
Define the term receptors ?
cells that detect a change
39
Define the term modulator ?
receives the message and coordinates a response
40
Define the term response ?
cause of action
41
Define the term effector ?
muscle or gland that causes a response
42
Define the term feedback ?
how the stimulus changes
43
What is the bodys optimum temperature ?
36.8
44
How is heat lost ?
-Evaporation: by sweat turning in to gas
-Convection: movement of air removes radiated heat
-Radiation: emissions of electromagnetic radiation
-Conduction: direct transfer of heat by contract
45
What are physiological response to hot and cold conditions ?
sweating
vasodilation
Vasoconstriction
shivering
piloerection
changes to the metabolic rate
46
What is sweating ?
when external temp is above 28 sweat is released by the sweat glands to cool the body through evaporation.
47
What is vasoconstriction ?
impulses from the hypothalamus via the sympathetic nerves cause smooth muscles in the arterioles in the skin to prevent heat loss through radiation
48
What is vasodilation ?
impulses from the hypothalamus via the sympathetic nerves cause smooth muscles in the arterioles in the skin to relax increasing blood flow and heat loss due to radiation
49
What is shivering ?
Continuous contraction and relaxation of the skeletal muscle no work is done so all energy goes towards heating up the body.
50
What is piloerection
hair standing up on end to trap heat
51
what hormones increase metabolic rate consequently increase body temperature?
thyroxine, adrenaline and noradrenaline
52
where are the places fluid id distributed in the body ?
intracellular
extracellular
intravascular
Interstitial
trancellular
53
where is the intracellular fluid ?
inside the cell membrane
54
Where is the extracellular fluid ?
outside the cell membrane
55
where is the intravascular fluid ?
inside the blood vessels
56
where is the interstitial fluid ?
in between the cells
57
where is the transcellular fluid ?
specific body regions eg eyes
58
what is osmotic pressure?
the movement of water to areas of high concentration of dissolved solute
59
what is the fluid balance ?
the fluid that is lost must be equal to the fluid that is consumed
60
what is excretion ?
the removal of waste products of metabolism from the body
61
What does antidiuretic hormone control ?
the active reabsorption of water in to the distal convoluted tubules and collecting tubule
62
What does antidiuretic hormone do to increase the water content in the body ?
increases the permeability of the distal convoluted tubules and collecting tubule which decreases the water content in the urine resulting in a increase of water in the blood.
63
what is aldostrones role in fluid regulation ?
acts on the distal convoluted tubules and collecting tubule to increase sodium ions reabsorbed into the bloodstream.
64
what is the process of turning glucose into glycogen called?
glycogenesis
65
what is the process of turning glycogen back in to glucose called?
glycogenolysis
66
what is the role of the pancreas?
-contains the islet of langerhans which create alpha and beta cells to create glucagon and insulin
-it also contains chemoreceptors which detects change in the blood glucose levels
67
what is the role of the pancreas in relations to insulin ?
-accelerate the transport of glucose from the body into body cells
-accelerate the conversion of glucose into glycogen in the liver and skeletal muscle
-stimulate the conversion of glucose into protein
-stimulates the conversion of glucose into fat.
68
what is the role of the pancreas in relations to glucagon?
-stimulates glycogenolysis
-stimulates gluconeogenesis
-induces some protein break down
69
What is the role of the adrenal cortex in glucose regulation?
-ACTH stimulates the release of glucocorticoids
-glucocorticoids ensure that enough energy is provided to the cell stimulating glycogenolysis
-increase the transportation of amino acids to the liver
-allows muscle cells to shift from using glucose to using fatty acids for metabolic energy
70
What is the role of the adrenal medulla in glucose regulation?
-release of adrenaline and noradrenaline
-increases blood glucose levels by glycogenolysis
-stimulates the production of lactic acid from glycogen in the muscles used to make glucose in the liver
71
what is the chemical reaction for regulation of gas ?
CO2 + H2O <-> H2CO3 <-> HCO-3 + H+
carbon dioxide + water <-> carbonic acid <-> bicarbonate + hydrogen ions
72
what does an increase in carbon dioxide do to the body ?
increase the levels of hydrogen ions which makes the blood more acidic
73
what are chemoreceptors sensitive too?
-carbon dioxide
-oxygen
-hydrogen ions
74
What are the two types of chemoreceptors ?
peripheral
central
75
what do the peripheral chemoreceptors do and where are the located?
a group of cells within the walls of the aorta and carotid artery
that detects changes in the oxygen, carbon dioxide, hydrogen levels in the plasma
76
what do the central chemoreceptors do and where are the located?
located in the medulla oblongata
detects changes in carbon dioxide and hydrogen ions concentrations in the cerebrospinal fluid
77
why does oxygen not have a major role in maintaining regular breathing rhythm?
because levels have to get too low for a major stimulating effect
78
why does the concentration of carbon dioxide play a major role in the regulation of breathing?
a small change will stimulate a large increase in rate an depth of breathing because chemoreceptors are more sensitive
79
what are the physical barriers in the external non-specific defences?
-skin
-mucus
-hairs
-cilia
80
how does the skin provide a defence to the body ?
-sebum-oily secretion that kills some pathogenic bacteria
-sweat - salt and fatty acids that prevent bacteria growth
81
how does the mucus provide a defence to the body ?
-goblet cells produce mucus which traps particles
-mucus membrane lines the body cavities that open to the exterior
82
how does the hair provide a defence to the body ?
-found in the nasal cavity and trap the particles form getting into the body
83
how does the cilia provide a defence to the body ?
- tiny hair like projections that beat
-able to move trapped particles in mucus up towards the throat
84
what are the chemical barriers in the external non-specific defences?
-Acid
-Lysozyme
85
how does the Acid provide a defence to the body ?
- kills the bacteria
located mainly in the stomach, vagina and sweat
86
how does the lysozymes provide a defence to the body ?
-enzymes that kill bacteria
- found in tears, sweat and nose secretion
87
what are some extra external defences?
movement of water
88
how does the movement of water provide a defence to the body ?
-urine through the uretha
-tear, sweat, saliva
89
what are protective reflexes?
Involuntary response to protect the body from injury or infection
90
what are some examples of protective reflexes?
-sneezing
-coughing
-vomiting
-diarrhoea
91
what is the types of granulocytes and what do they do ?
-Neutrophils: kills and digest harmful bacteria and fungi
-Basophils: releases histamines
-Eosinophils: fight bacteria and parasites allergy response
92
what is the types of agranulocytes and what do they do ?
- Monocytes: can differentiates into phagocytes (cleans up dead cell)
- lymphocytes: responsible for specific immune response
93
what is the types of granulocytes and what do they do ?
94
how does phagocytosis provide a internal defence to the body ?
-phagocytes white blood cells that engulf and digest debris and organisms
-neutrophils: first cell to move to tissue and destroy pathogens
-dendritic cells: uses info to assist with specific immune response
95
what are all of the internal defence systems?
-phagocytosis
-inflammation
-fever
-
96
what is the purpose of the inflammatory respones?
-reduce the spread of any pathogens
- remove damaged tissue and cell debris
-begin the repair of damaged tissue
97
what are the signs of an inflammatory response?
-redness
-pain
-swelling
-heat
98
what is the complement system ?
-50 proteins in made in the liver that are triggered when a pathogen enters the body that assist with the inflammatory response
99
what are the steps to the inflammatory response?
1. Break or tear in skin causing mast cells to release histamine and heparin
2. Histamine increases blood flow and permeability of capillaries to help fluid filter in blood
Heparin prevents clotting anywhere other than the infected area
3. Histamine releases phagocytes (macrophages) to digest micro-organisms and cell debris
4. Pain receptors are stimulated (signs of inflammation occur)
5. Phagocytes (macrophages) die and form yellow substance called pus
6. Mitosis occurs to produce more cells and repair old ones
100
what are the benefits of a fever?
-inhibit the growth of some microbes
-inhibit replication of viruses through the release of interferons
-speeds up chemical reaction in the body
101
what is a fever ?
an elevated body temperature where the bodys thermostat is set at a higher temperature
102
what causes the internal temp to be set higher?
pyrogens which is a interleukin-1
it acts on the hypothalamus
103
what is the process of having a fever?
1. Feelings cold because the body resets the body temperature to 39.5o Vasoconstriction of capillaries and shivering of skeletal muscle cells occurs, so the body temperature goes up
2. Fever breaks – body temperature goes back to original 37o
Sweat glands produce sweat and bacteria has been destroyed
3. Body temperature goes back to normal
104
where are the T and B lymphocytes produced?
in the bone marrow
105
where does the B lymphocyte mature?
in the bone marrow
106
where does the T lymphocyte mature?
in the thymas
107
what is an antigen ?
a substance capable of causing and immune response eg viruses, toxin, bacteria and pollen
108
what is and antibody?
a Y shaped protein that belongs to an immunoglobin protein group they work through the lock and key model
109
what is the process of Antibody-mediated immunity response ?
1. Antigen present in the blood or lymph
2. Bacteria is engulfed by macrophage (phagocytosis)
3. Lysosome is within vesicle, joins with bacteria
4. Enzymes will break down bacteria and broken into tiny
pieces
5. Cell debris, exocytosis
6. (presents antigen to surface)
7. Helper T-cell attaches and reads antigen: Antigen-antibody
complex
8. Releases and sends cytokines to activate B cells
9. B cells become sensitized
10. Specific B-cells enlarge and divide- creating clone
11. Creates memory B-cells and Plasma cells
Plasma cells create antibodies which bind to antigens Memory cells remember antigen for next time
110
what is the process of cell-mediated immunity response ?
1. Pathogen/antigen is present in a cell
2. Bacteria is engulfed by macrophage (phagocytosis) 3. Lysosome is within vesicle, joins with bacteria
4. Enzymes will break down bacteria and broken into tiny
pieces
5. Cell debris, exocytosis
6. (presents antigen to surface)
7. Helper T-cell attaches and reads antigen: Antigen-antibody
complex
8. Releases and sends cytokines to activate T-cells
9. T-cells become sensitized
10. T-cells enlarge and divide to create clone
11. Creates memory cells, killer T-cells, Helper T-cells and
suppressor T-cells
111
what is a memory cell?
- Inactivate substances (make a soluble substance insoluble) - Prevent virus from entering cells
- Coat bacteria for macrophages to come and engulf
- Agglutination (all clump together)
112
What are the four types of vaccines?
Live attenuated microorganisms
Inactivated vaccines
Toxoid vaccines
Sub-unit vaccine
113
what is the description of a live attenuated microorganism ?
* Microorganism is alive
* Reduced ability to produce disease symptoms
114
what is the description of a inactive vaccine ?
* Dead microorganism
* Shorter lasting immunity
115
what is the description of a toxoid vaccine ?
* Inactivated toxins – from bacteria (toxoids)
116
what is the description of a sub-unit vaccine ?
* Fragment of the organism is used as an antigen
117
what is an example of a sub-unit vaccine ?
HPV
Hepatitis B
118
what is an example of a toxoid vaccine ?
Diphtheria & tetanus
119
what is an example of a inactive vaccine ?
Cholera,
typhoid,
whooping cough
120
what is an example of a Live attenuated microorganisms vaccine ?
Polio,
tuberculosis,
rubella,
measles,
mumps,
yellow fever
121
what are antibiotic used to fight against ?
bacterial
122
what are antiviral used to fight against ?
virus/ viral infection
123
what is the afferent division ?
carries information into the CNS
124
what are the 2 sub division of afferent division and what do they do ?
somatic - sensory neurons from the skin or muscle
visceral - neurons from internal organs
125
what is the efferent division ?
carrying Information away from the CNS
126
what are the 2 divisions of the efferent division and what do the do?
Somatic- carrying messages to the skeletal muscle
Autonomic - carrying messages to heart and involuntary muscle and glands
127
What are the sub divisions of the autonomic division?
sympathetic
Parasympathetic
