The central nervous system/homeostasis/immunity Flashcards
what is the CNS comprised of?
brain and spinal cord
what protects the CNS?
bones
meniges
cerebrospinal fluid
what is the function of the cerebrospinal fluid?
protects- being a shock absorber
supports - brain floats in it
transports- nutrition and waste
what is the meninges comprise of?
Dura mater
Arachnoid mater
Pia mater
what is the dura mater?
a thick durable layer attached to the skull
What is the arachnoid mater?
attached to the dura mater to provide a cushion effect
what is the Pia mater?
thin membrane that follows the gyri and sulci
draw the diagram of the spinal cord ?
must include grey matter central canal which contain cerebrospinal fluid and white matter
what is a ascending movement ?
a sensory axon that carry a nerve impulse towards the brain
what is a descending movement?
motor axon that carry impulses away from the brain
what are neurons?
highly specialised cells that carry’s information form one part of the body top another
what do glial cells do ?
supports, protects, provides nutrition and insulates them from each other
what is an afferent neuron?
takes nerve impulses from the receptors to the central nervous system
what is an efferent neuron?
take nerve impulses from the central nervous system to the effector structure
what is an interneuron?
they link sensory neurons and motor neurons together
what are the four types of neuron ?
unipolar
bipolar
multipolar
pseudo-unipolar
what is the structure of a unipolar neuron ?
has on extension from the cell body to the axon terminal
what is the structure of a bipolar neuron ?
a distinct axon and have a dendritic fibre that is separated by a cell body
what is the structure of a multipolar neuron ?
have a single axon and several dendritic fibres
what is the structure of a pseudo-unipolar neuron ?
a single axon from a cell body which branches of into dendrites an axon terminals
what are propertise and characteristics of a dendrite ?
short and highly branched
synapses with other neurons or receptors
transmit the electrochemical impulse towards the cell body
what are propertise and characteristics of axon ?
Typically a single long nerve fibre
terminate at synaptic end bulbs
connects with muscles, glands and other neurons
what is the myelin sheath ?
a fatty white sheath that surrounds the axon on most neurons
what is the myelin sheath created by ?
schwann cells
what is a benefit of a neuron having a myelin sheath ?
transmission of nerve impulse occurs faster
what are the gaps between the sheaths called ?
the node of ranvier
what is a reflex ?
a rapid automatic response to a change in the internal and/or external environment
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.
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
what are the two types of relfex?
Innate
Acquired
what is an innate reflex?
a relex that is built in as apart of being a human eg suckling grasping
What is a acquire reflex?
a reflex that is learnt eg catching a ball
Describe the process of action potential ?
- 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
- Depolarisation – when action potential is created from sodium ions allowed into the cell
- Repolarisation – ion channels on the inside of the membrane allow potassium ions out: this restores the electrical balance
- 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 - 1-4 steps refractory period – the brief time during and after-action potential when the neuron cannot be stimulated
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
Describe the process of transmission across a synapse?
- Membrane depolarises – the end of an axon, calcium gates will open, letting calcium ions enter the cell
- Synaptic vesicle release neurotransmitters – relay message between neurons
- Neurotransmitters bind with receptors – bind on the neuron (acetylcholine, dopamine, adrenaline)
- 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
What is the definition of homeostasis ?
the process by which the bodys internal environment is maintained at a steady state.
Define the term stimulus ?
a change in the internal and external environment
Define the term receptors ?
cells that detect a change
Define the term modulator ?
receives the message and coordinates a response
Define the term response ?
cause of action
Define the term effector ?
muscle or gland that causes a response
Define the term feedback ?
how the stimulus changes
What is the bodys optimum temperature ?
36.8
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
What are physiological response to hot and cold conditions ?
sweating
vasodilation
Vasoconstriction
shivering
piloerection
changes to the metabolic rate
What is sweating ?
when external temp is above 28 sweat is released by the sweat glands to cool the body through evaporation.
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
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
What is shivering ?
Continuous contraction and relaxation of the skeletal muscle no work is done so all energy goes towards heating up the body.
What is piloerection
hair standing up on end to trap heat
what hormones increase metabolic rate consequently increase body temperature?
thyroxine, adrenaline and noradrenaline
where are the places fluid id distributed in the body ?
intracellular
extracellular
intravascular
Interstitial
trancellular
where is the intracellular fluid ?
inside the cell membrane
Where is the extracellular fluid ?
outside the cell membrane
where is the intravascular fluid ?
inside the blood vessels
where is the interstitial fluid ?
in between the cells
where is the transcellular fluid ?
specific body regions eg eyes
what is osmotic pressure?
the movement of water to areas of high concentration of dissolved solute
what is the fluid balance ?
the fluid that is lost must be equal to the fluid that is consumed
what is excretion ?
the removal of waste products of metabolism from the body
What does antidiuretic hormone control ?
the active reabsorption of water in to the distal convoluted tubules and collecting tubule
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.
what is aldostrones role in fluid regulation ?
acts on the distal convoluted tubules and collecting tubule to increase sodium ions reabsorbed into the bloodstream.
what is the process of turning glucose into glycogen called?
glycogenesis
what is the process of turning glycogen back in to glucose called?
glycogenolysis
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
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.
what is the role of the pancreas in relations to glucagon?
-stimulates glycogenolysis
-stimulates gluconeogenesis
-induces some protein break down
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
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
what is the chemical reaction for regulation of gas ?
CO2 + H2O <-> H2CO3 <-> HCO-3 + H+
carbon dioxide + water <-> carbonic acid <-> bicarbonate + hydrogen ions
what does an increase in carbon dioxide do to the body ?
increase the levels of hydrogen ions which makes the blood more acidic
what are chemoreceptors sensitive too?
-carbon dioxide
-oxygen
-hydrogen ions
What are the two types of chemoreceptors ?
peripheral
central
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
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
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
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
what are the physical barriers in the external non-specific defences?
-skin
-mucus
-hairs
-cilia
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
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
how does the hair provide a defence to the body ?
-found in the nasal cavity and trap the particles form getting into the body
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
what are the chemical barriers in the external non-specific defences?
-Acid
-Lysozyme
how does the Acid provide a defence to the body ?
- kills the bacteria
located mainly in the stomach, vagina and sweat
how does the lysozymes provide a defence to the body ?
-enzymes that kill bacteria
- found in tears, sweat and nose secretion
what are some extra external defences?
movement of water
how does the movement of water provide a defence to the body ?
-urine through the uretha
-tear, sweat, saliva
what are protective reflexes?
Involuntary response to protect the body from injury or infection
what are some examples of protective reflexes?
-sneezing
-coughing
-vomiting
-diarrhoea
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
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
what is the types of granulocytes and what do they do ?
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
what are all of the internal defence systems?
-phagocytosis
-inflammation
-fever
-
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
what are the signs of an inflammatory response?
-redness
-pain
-swelling
-heat
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
what are the steps to the inflammatory response?
- Break or tear in skin causing mast cells to release histamine and heparin
- Histamine increases blood flow and permeability of capillaries to help fluid filter in blood
Heparin prevents clotting anywhere other than the infected area - Histamine releases phagocytes (macrophages) to digest micro-organisms and cell debris
- Pain receptors are stimulated (signs of inflammation occur)
- Phagocytes (macrophages) die and form yellow substance called pus
- Mitosis occurs to produce more cells and repair old ones
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
what is a fever ?
an elevated body temperature where the bodys thermostat is set at a higher temperature
what causes the internal temp to be set higher?
pyrogens which is a interleukin-1
it acts on the hypothalamus
what is the process of having a fever?
- 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
- Fever breaks – body temperature goes back to original 37o
Sweat glands produce sweat and bacteria has been destroyed - Body temperature goes back to normal
where are the T and B lymphocytes produced?
in the bone marrow
where does the B lymphocyte mature?
in the bone marrow
where does the T lymphocyte mature?
in the thymas
what is an antigen ?
a substance capable of causing and immune response eg viruses, toxin, bacteria and pollen
what is and antibody?
a Y shaped protein that belongs to an immunoglobin protein group they work through the lock and key model
what is the process of Antibody-mediated immunity response ?
- Antigen present in the blood or lymph
- Bacteria is engulfed by macrophage (phagocytosis)
- Lysosome is within vesicle, joins with bacteria
- Enzymes will break down bacteria and broken into tiny
pieces - Cell debris, exocytosis
- (presents antigen to surface)
- Helper T-cell attaches and reads antigen: Antigen-antibody
complex - Releases and sends cytokines to activate B cells
- B cells become sensitized
- Specific B-cells enlarge and divide- creating clone
- Creates memory B-cells and Plasma cells
Plasma cells create antibodies which bind to antigens Memory cells remember antigen for next time
what is the process of cell-mediated immunity response ?
- Pathogen/antigen is present in a cell
- Bacteria is engulfed by macrophage (phagocytosis) 3. Lysosome is within vesicle, joins with bacteria
- Enzymes will break down bacteria and broken into tiny
pieces - Cell debris, exocytosis
- (presents antigen to surface)
- Helper T-cell attaches and reads antigen: Antigen-antibody
complex - Releases and sends cytokines to activate T-cells
- T-cells become sensitized
- T-cells enlarge and divide to create clone
- Creates memory cells, killer T-cells, Helper T-cells and
suppressor T-cells
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)
What are the four types of vaccines?
Live attenuated microorganisms
Inactivated vaccines
Toxoid vaccines
Sub-unit vaccine
what is the description of a live attenuated microorganism ?
- Microorganism is alive
- Reduced ability to produce disease symptoms
what is the description of a inactive vaccine ?
- Dead microorganism
- Shorter lasting immunity
what is the description of a toxoid vaccine ?
- Inactivated toxins – from bacteria (toxoids)
what is the description of a sub-unit vaccine ?
- Fragment of the organism is used as an antigen
what is an example of a sub-unit vaccine ?
HPV
Hepatitis B
what is an example of a toxoid vaccine ?
Diphtheria & tetanus
what is an example of a inactive vaccine ?
Cholera,
typhoid,
whooping cough
what is an example of a Live attenuated microorganisms vaccine ?
Polio,
tuberculosis,
rubella,
measles,
mumps,
yellow fever
what are antibiotic used to fight against ?
bacterial
what are antiviral used to fight against ?
virus/ viral infection
what is the afferent division ?
carries information into the CNS
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
what is the efferent division ?
carrying Information away from the CNS
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
What are the sub divisions of the autonomic division?
sympathetic
Parasympathetic
