HHB - Whole Course

Brain and spinal cord

The somatic nervous system and autonomic nervous system

Sensory and motor

Take impulses from sense organs to the CNS

Take impulses from the CNS to muscles and glands.

Sympathetic and parasympathetic

Antagonistic

Speed up heart rate
Speeds up breathing rate
Slows down peristalsis
Slows down the production of intestinal secretions

Slows down heart rate
Slows down breathing rate
Speeds up intestinal secretions
Speeds up the production of intestinal secretions

Impulses from several neurons travel to one neuron

Increases the sensitivity to excitatory or inhibitory signals

Impulses from one neuron travel to several neurons

It can affect more than one destination at the same time

Neurons later in the pathway link with earlier neurons sending the impulse back through the pathway

Allows for repeated stimulation of the pathway

Centre of conscious thought
Recalls memories
Alters behaviour in the light of experience

Localisation of brain functions

Sensory areas
Motor areas
Association areas

language processing
imagination
personality
intelligence

The opposite side of the cerebrum

The corpus callosum

A bundle of nerves connecting the two hemispheres of the cerebrum.

encoding
storage
retrieval of information

Past experience
knowledge
Thoughts

All the visual and auditory input received for a few seconds

Selected images and sounds

It has a limited capacity and holds information for a short time

The number of items which a person can retain and recall in STM.

The tendency of a person to recall the first and last items in a series best, and the middle items worst

A piece of information is repeated to retain it in STM long enough to complete a task

Displacement
Decay

When STM becomes full, new information pushes out old information

Memories are forgotten over the passage of time if they are not reinforced, rehearsed or transferred to LTM

The STM can process data to a limited extent, allowing it to perform simple cognitive tasks

Unlimited

Rehearsal
Organisation
Elaboration

A shallow form

Deeper form, leading to improved information retention

Use of contextual cues

They relate to the time and place when the information was initially encoded into LTM

Dendrites
Cell Body
Axon

They receive nerve impulses and carry them towards the cell body

It contains the nucleus and most of the cytoplasm

Carries nerve impulses away from a cell body into the next neuron

Axons are surrounded by a myelin sheath which insulates the axon and increases the speed of impulse conduction

The formation of a myelin sheath around an axon, it continues from birth to adolescence

They are not as rapid or coordinated in the first two years of life due to less myelination

They produce the myelin sheath and support neurons

Other neurons or muscle fibres

Chemicals which relay impulses across the synaptic cleft

In vesicles in the axon endings of the presynaptic neuron

They diffuse across the synaptic cleft and bind to receptors on the membrane of the postsynaptic neuron

To prevent continuous stimulation of postsynaptic neurons

Enzyme degradation
Re-uptake

Whether the signal is excitatory or inhibitory

Causes a nerve impulse in the postsynaptic neuron

Reduces the chances of an impulse in the post-synaptic neuron

Weak stimuli arising from insufficient secretion of neurotransmitters.

A minimum number of neurotransmitter molecules must attach to receptors in order to reach the threshold on the postsynaptic membrane to transmit the impulse

A series of weak stimuli can release enough neurotransmitter to trigger an impulse.

Convergent neural pathways

Neurotransmitters that stimulate neurons involved in reducing the intensity of pain

Feelings of pleasure obtained from activities such as eating, sex and prolonged excercise

Severe injury, prolonged and continuous exercise, stress and certain foods.

A neurotransmitter that induces feelings of pleasure

It reinforces particular behaviour by activating the reward pathway in the brain

it involves neurons which secrete or respond to dopamine, it is activated when an individual engages in a behaviour that is beneficial to them.

Agonists or antagonists

Chemicals that bind to and stimulate specific receptors mimicking the action of a neurotransmitter at a synapse

Chemicals that bind to specific receptors blocking the action of a neurotransmitter at a synapse

Inhibiting the enzymes that degrade neurotransmitters
Inhibiting reuptake of the neurotransmitter at the synapse causing an enhanced effect.

Agonists or Antagonists

Affect neurotransmission in the reward pathway and the synapses in the brain altering an individual's mood, cognition, perception and behaviour

They block specific receptors causing the nervous system to increase both the number and sensitivity of these receptors. This sensitisation leads to addiction where the individual craves more of the drug

They stimulate specific receptors causing the nervous system to decrease the number and sensitivity of these receptors. This desensitisation leads to drug tolerance where the individual must take more of the drug to get an effect.

A bacterium, virus or other organism that can cause disease

A physical barrier

Skin
Inner lining of the digestive system
Inner lining of the respiratory system

Chemical secretion such as saliva, mucus, tears and stomach acid

Histamine, causing vasodilation and increased capillary permeability

An accumulation of phagocytes and clotting elements at the site of infection

Recognise pathogens and destroy them by phagocytosis

Pathogens are engulfed by a phagocytic cell and the pathogen is destroyed by digestive enzymes contained in lisosomes

Cytokines which attract more phagocytes to the site of infection

Protein molecule that act as a signal to specific white blood cells causing them to accumulate at the site of infection

The white blood cells involved in the specific immune response

Molecules located on the surface of cells that trigger a specific immune response

Specific antigens on invading pathogens

specific to one antigen

Repeated lymphocyte division resulting in the formation of a clonal population of identical lymphocytes

B Lymphocytes and T Lymphocytes

They produce antibodies against antigens which leads to the destruction of the pathogen

Y-shaped proteins that have receptor binding sites specific to a particular antigen on a pathogen.

Inactivates the pathogen and forms an antigen-antibody complex which can be destroyed by phagocytosis.

B Lymphocytes respond to antigens on substances that are harmless to the body

They destroy infected body cells by recognising antigens of the pathogen on the cell membrane and inducing apoptosis.

Programmed cell death

Release proteins

They diffuse into the infected cells causing production of self-destructive enzymes causing cell death.

They are removed by phagocytosis

They can normally distinguish between self-antigens on the body's own cells and non-self-antigens on infected cells

Failure of the regulation of the immune system leads to T Lymphocytes responding to self-antigens.

The body's own cells

Memory cells

A new clone of specific lymphocytes

It is greater and more rapid

Attacks and destroys T lymphocytes

T lymphocytes which leads to the development of AIDS

They have a weakened immune system and are more vulnerable to opportunistic infections

By using antigens from infectious pathogens to stimulate the body to create memory cells

Inactivated pathogen toxins
Dead pathogens
Parts of pathogens
Weakened pathogens

Adjuvant

A substance which makes the vaccine more effective and enhances the immune response

When a large percentage of a population is immunised

It reduces the spread of diseases

Non-immune individuals are protected as there is a lower probabiity they will come into contact with infected individuals

The percentage of the population which must be vaccinated to achieve herd immunity

Type of disease
Effectiveness of vaccine
Population density

Establish herd immunity to a disease

Poverty in the developing world
A percentage of the population in the developed world rejects the vaccines

When some pathogens can change their antigens. This means that memory cells are not effective against them.

This explains why it remains a major public health problem despite vaccination programmes. Individuals who are at risk need to be vaccinated every year.

To establish their safety and effectiveness before being licensed for use

Subjects are divided into groups in a randomised way to reduce bias in the distribution of characteristics such as age and gender

Neither the subjects nor the researchers know which group subjects are in to prevent biased interpretation of the results

One group of subjects receives the vaccine or drug while the second group receives a placebo-control to ensure valid comparisons

This reduces the magnitude of experimental error and allows for comparison between groups to identify any statistically significant differences.

They produce sperm in the seminiferous tubules and testosterone in the interstitial cells

To secrete fluids that maintain the mobility and viability of the sperm

Immature ova in various stages of development

A follicle which protects the developing ovum and secretes hormones

They may be fertilised by sperm to form a zygote

The hypothalamus secretes a releaser hormone which stimulates the pituitary gland to release FSH, LH in females or ICSH in males

Promotes sperm production

Stimulates the production of testosterone

Stimulates sperm production and activates the prostate gland and seminal vesicles

As the concentration of testosterone builds up in the bloodstream it reaches a level where it inhibits the secretion of FSH and ICSH by the pituitary gland. This leads to a decrease in testosterone concentration which triggers the pituitary gland to make FSH and ICSH.

Approximately 28 days

Blood Flow

Follicular Phase and Luteal Phase

Stimulates the development and maturation of a follicle and stimulates the follicle to secrete oestrogen

Brings about the development of the corpus luteum from the follicle and stimulates the corpus luteum to secrete progesterone

Stimulates proliferation of the endometrium and prepares it for implantation.

Makes it more easily penetrated by sperm

A surge in LH which triggers ovulation

The release of an egg from the ovary which usually occurs at the midpoint of the menstrual cycle

Promotes further development and vascularisation of the endometrium, preparing it for implantation if fertilisation occurs

High levels of progesterone inhibit the secretion of FSH and LH by the pituitary gland, which inhibits the secretion of Progesterone and Oestrogen

The concentration of oestrogen builds up, stimulating the proliferation and repair of the endometrium and preparing it for implantation as well as affecting the cervical mucus so that it is more easily penetrated by sperm
Peak levels of oestrogen stimulate a surge in the secretion of LH and FSH by the pituitary gland
The surge of LH triggers ovulation
The ovum moves along the oviduct

LH stimulates the follicle to become the corpus luteum
The corpus luteum secretes progesterone
The rise is progesterone concentration stimulates further development of the endometrium so it becomes thick, spongy and has an increase in vascular blood vessels
High levels of oestrogen and progesterone trigger and inhibitory effect on the pituitary gland, so concentrations of FSH and LH drop as a result and no new follicles develop at this time

The drop of LH leads to the degeneration of the corpus luteum
There is a rapid drop in progesterone
By approximately day 28 the ovarian hormones are so low that the endometrium cannot be maintained and menstruation begins
Menstruation, which involves the loss of the inner layer of the endometrium accompanied by a small volume of blood, occurs

The embryo secretes a hormone called HCG which has the same effect as LH
HCG maintains the corpus luteum which continues to secrete progesterone and prevents menstruation taking place
After about 6 weeks the placenta takes on the job of secreting progesterone

The presence of HCG in urine

Cyclical Fertility. This means they are only fertile for a few days during each menstrual cycle, immediately after ovulation

Continuous fertility. This means they continually produce sperm in their testes

Her body temperature rises by 0.5 degrees after ovulation and her cervical mucus becomes thin and watery

Several samples of semen are collected over a period of time and frozen until required. When ready,, the semen are defrosted and released into the female's cervix during her fertile period.

If the male has a low sperm count

The head of a sperm is drawn into a needle and injected directly into the egg to achieve fertilisation

If mature sperm or defective or the man has a low sperm count

Woman is given hormonal treatment to stimulate super ovulation
Eggs are surgically removed
Eggs are mixed with sperm in a culture dish
The fertilised eggs are incubated until they have formed at least 8 cells
The zygotes are then transferred to the uterus for implantation

To identify single gene disorders and chromosomal abnormalities

Condom
Diaphragm
Cervical Cap

It is a T-shaped device that is fitted into the uterus to prevent implantation of an embryo

In men, a vasectomy involves cutting and tying the two sperm ducts. This prevents sperm being released during sex
In women, a tubal ligation involves cutting and tying the two oviducts. This prevents eggs meeting sperm and reaching the uterus.

Oral contraceptive pill
Emergency hormonal contraceptive pills
synthetic progesterone

Contains a combination of synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland.

Causes thickening of the cervical mucus, making it harder for sperm to reach the egg

Prevents or delays ovulation

To identify the risk of a disorder so that further tests and a prenatal diagnosis can be offered

A dating scan between 8 and 14 weeks
An anomaly scan between 18 and 20 weeks

This determines the pregnancy stage and due date.
It is used in conjunction with blood and urine tests for marker chemicals which vary normally during pregnancy

To detect serious physical abnormalities in the foetus

To monitor the concentrations of marker chemicals

This cold lead to a false positive result

Diagnostic testing to determine if the foetus has a medical condition

Amniocentesis and Chorionic Villus Sampling

Amniotic fluid containing fetal cells

14-16 weeks

There is a lower risk of miscarriage than CVS

Cells need to be cultured before the karyotype can be done which can take 2 weeks

Placenta

8 weeks

Karyotyping is carried out on fetal cells immediately

There is a higher risk of a miscarriage than in amniocentesis

An individual's chromosomes arranged as homologous pairs. This allows diagnosis of genetic conditions where chromosomes are missing or extra copies are present

This occurs when the baby is a few days old and involves having their blood tested for the presence of excess phenylalanine

A substitution mutation which means the enzyme which converts phenylalanine into tyrosine is non-functional

They are put on a restricted diet.

an organism's characteristics

Different forms of a gene

The physical appearance of an organism

This is the two copies of a gene that every individual has

The allele which is always expressed in the phenotype

An allele only expressed if an organism has two copies of it

They have two alleles which are the same for that characteristic

They have two different alleles for that characteristic

The trait may skip generations
Genotypes of sufferers are homozygous recessive
Genotypes of non-sufferers are homozygous dominant or heterozygous

The trait is expressed in every generation
Each sufferer of the trait has an affected parent
Genotypes of sufferers are homozygous dominant or heterozygous
Genotypes of non-sufferers are homozygous recessive

Each sufferer of the fully expressed form has two parents who suffer from the partly expressed form
All non-sufferers are homozygous for one incompletely dominant allele
All sufferers of the fully expressed form are homozygous for the other incompletely dominant allele
All sufferers of the partly expressed form are heterozygous for the two alleles

An affected male cannot pass the trait on to his son
Some grandsons of an affected male show the trait
All sufferers of the trait are homozygous recessive
Non-sufferers are homozygous dominant or heterozygous carrier females

From the heart through the arteries to the capillaries, then to the veins and back to the heart.

It decreases

The walls are thick and strong. The outer layer is composed of connective tissue containing elastic fibres. The middle layer is composed of muscle. The inner layer is made up elastic fibres and an endothelium lining.
Have a narrow lumen
Don't have any valves
Divided up into arterioles

The walls are very thin
Have a very narrow lumen
Don't have any valves

Thin Walled. The outer layer is made of connective tissue containing elastic fibres, the middle layer is composed of muscle, the inner layer contains elastic fibres and the endothelium lining.
Have a wider lumen than arteries
Have valves

Venules

Blood is transported from arterioles to venules by passing through the dense network of capillaries. Their thin walls and narrow lumen allow for materials to be easily exchanged with the tissues.

Carry blood away from the heart at high pressure. The strength and elasticity of their walls allow them to withstand the pulsing of blood, prevent bursting, maintain blood pressure, and carry out vasoconstriction and vasodilation.

Arterioles

Carry blood to the heart at low pressure. Their wide lumen allows for less resistance to blood flow and the valves prevent the backflow of blood.

Layers of tissue

They stretch and recoil to accommodate the surge of blood after each contraction of the heart.

The smooth muscle surrounding arteries contracts to allow less blood flow

The smooth muscle surrounding arteries relaxes to allow more blood flow.

Tissue fluid doesn't contain plasma proteins, as they are too large to be filtered through the capillary walls

Plasma passes through capillary walls into the tissue fluid surrounding the cells

To supply cells with glucose, oxygen and other substances

They diffuse out of the cells and into the tissue fluid to be excreted

A lot

They absorb excess tissue fluid and return it as lymph to the circulatory system.

The volume of blood pumped through each ventricle per minute

heart rate x stroke volume

No

When the heart muscle is relaxed and the chambers fill with blood

When the atria walls contract

When the ventricular walls contract

During diastole. blood returning to the atria flows into the ventricles.
Atrial systole transfers the remainder of the blood through the atrio-ventricular valves to the ventricles
Ventricular systole closes the atrio-ventricular valves and pumps the blood out through the semi lunar valves to the aorta and pulmonary artery

The higher blood pressure in the arteries

The atrio-ventricular valves close

The semi lunar valves close

The opening and closing of the atrio-ventricular and semi-lunar valves

SAN cells

It generates electrical impulses and passes them across the heart muscle causing it to contract in a co-ordinated sequence

In the heart

They can generate their own electrical signal themselves, without stimulation by a neuron

In the wall of the right atrium

The auto-rhythmic cells of the SAN

Impulses from the SAN spreading through the atria causing atrial systole

The atrioventricular node located in the centre of the heart

They travel down fibres in the central wall of the heart and then up through the walls of the ventricles, causing ventricular systole

Currents generated by impulses in the heart.

The rate of the sinoatrial node through the antagonistic action of the autonomic nervous system

Noradrenaline which increases the heart rate

Acetylcholine which decreases the heart rate

It increases during ventricular systole and decreases during diastole

A sphygmomanometer

120/80 mmHg

An inflatable cuff is placed around the arm, it inflates to stop blood flow in the artery, then deflates gradually. As it deflates, the blood starts to flow, detected by a pulse, at systolic pressure. When the blood flows freely through the artery, and a pulse is not detected, this is the value of diastolic pressure

High blood pressure, it is a major risk factor for many diseases including coronary heart disease

The accumulation of fatty material beneath the endothelium of an artery, resulting in increased blood pressure.

Fatty material, fibrous material and calcium

Artery's lumen becomes narrower
Blood flow to the capillary bed is restricted
Blood pressure increases
The artery walls lose elasticity due to deposits of calcium and harden

Angina, heart attack, stroke and peripheral vascular disease

Atheromas may rupture, damaging the endothelium.
This damage releases clotting factors which convert the inactive enzyme prothrombin into the active enzyme thrombin.
Thrombin then catalyses the reaction in which fibrinogen becomes fibrin.
Fibrin threads form a meshwork that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue

A thrombus may break loose forming an embolus which travels through the bloodstream until it blocks a blood vessel

A heart attack

A stroke

Myocardial infarction

They are deprived of oxygen, leading to the death of the tissues.

The narrowing of the arteries other than those of the heart or brain

Arteries to the legs

Pain is experienced in the leg muscles due to a limited supply of oxygen

A blood clot that forms in a deep vein, commonly in the leg. This can break off and result in a pulmonary embolism in the lungs

A type of lipid found in the cell membrane

Sex hormones testosterone, progesterone and oestrogen

The liver

A diet high in saturated fats or cholesterol

Transports excess cholesterol from the body cells to the liver for elimination, preventing accumulation of cholesterol in the blood.

Transports cholesterol to body cells

Most cells have LDL receptors that take LDL into the cell where it releases cholesterol

Once a cell has sufficient cholesterol a negative feedback system inhibits the synthesis of new LDL receptors and LDL circulates in the blood where it may deposit the cholesterol in the arteries forming atheromas.

Lower blood cholesterol and a reduced chance of atherosclerosis

Regular physical activity tends to raise HDL levels

Dietary changes aim to reduce the levels of total fat in the diet and to replace saturated fats with unsaturated fats

Drugs such as statins reduce blood cholesterol by inhibiting the synthesis of cholesterol by liver cells

The endothelium cells taking in more glucose than normal, damaging the blood vessels

Atherosclerosis, which may lead to stroke, CVD or PVD

Haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction

They increase secretion of insulin from the pancreas

It activates the conversion of glucose to glycogen in the liver, decreasing blood glucose concentration

They increase secretion of glucagon from the pancreas

It activates the conversion of glycogen to glucose in the liver, increasing blood glucose concentration

Adrenaline released from the adrenal gland which stimulates glucagon secretion and inhibits insulin secretion

Childhood

Insulin, this can be treated with regular doses of insulin

Adulthood

Individuals produce insulin but their cells are less sensitive to it due to a decrease in the number of insulin receptors in the liver, leading to a failure to convert glucose to glycogen

Their blood glucose concentrations will rise rapidly

Glucose appearing in urine. Testing urine for glucose is an indicator of diabetes.

The blood glucose concentrations of an individual are measured after fasting. The individual drinks a glucose solution and changes in their blood glucose concentration are measured for at least the next two hours.

Their blood glucose concentration usually starts at a higher level than that of a non-diabetic.
During the test, their blood glucose concentration increases to a much higher level than that of a non-diabetic.
Their blood glucose levels take longer to return to the starting concentration

CVD and type 2 diabetes

Excess body fat in relation to lean body tissue

It may impair health

Body mass index, but it can wrongly classify muscular individuals as obese

Weight in kg divided by height in metres squared

Above 30

High fat diets and a decrease in physical activity

Fats have a high calorific value per gram and free sugars require no metabolic energy to be expended in their digestion