HIV (Edexcel Biology Unit 4 A2)

Summary sheet of HIV and AIDS

Biology Unit 4 A2 Edexcel

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  • Created by: Niki :)
  • Created on: 13-05-13 13:12
Preview of HIV (Edexcel Biology Unit 4 A2)

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By Niki Nubi
Symptoms
How it is transmitted
Normal symptoms HIV-related symptoms
· Via sexual contact. Fever Weight loss
Headaches Fatigue
· Through infected blood, through intravenous drug use.
Tiredness Diarrhoea
· From a mother to a foetus, during birth or through
Swollen glands Low-grade infections
breastfeeding. Night sweats
Controlling infection
· Education programmes
· Less promiscuous sex
· Use of condoms
· Use of clean needles
Stages of infection
· Stage 1: ACUTE HIV SYNDROME
o Experience symptoms in the first few weeks
o HIV antibodies appear in the blood 3-12 weeks after infection
Cause of AIDS
· Stage 2: ASYMPTOMATIC STAGE
o All symptoms disappear · HIV binds to CD4 receptors on the T helper cells and infects them.
o The virus replicates, infecting CD4 T helper cells. · HIV takes over the host DNA and replicates.
o Secondary infections develop · When the new virus leaves the host cell, it is destroyed.
· Stage 3: SYMPTOMATIC DISEASE · T killer cells destroy some of the heavily infected T helper cells.
o Immune system starts to fail · The number of T helper cells decreases so macrophages and T killer cells
o T helper cell count falls rapidly aren't activated. The T helper cells can't function properly.
o Patients suffer HIV-related symptoms
· Increased vulnerability to secondary infections.
· Stage 4: ADVANCED AIDS
o Severe symptoms appear (weight loss, dementia, cancers, TB)
· Final Stage: DEATH

Comments

asha


This is really good, thanks

TTFSam

Beautifully drawn-up thanks!

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