Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 45

Cells which contain their DNA within a nuclear membrane are referred to as eukaryotic cells. The cells which make up the bodies of animals (including humans), plants and fungi are all eukaryotic. Human erythrocytes (red blood cells) lose their nucleus as they mature; this loss of the nucleus allows more haemoglobin molecules to be packed into the cell, improving the efficiency of oxygen transport. However, since erythrocytes are derived from nucleated cells, they are still eukaryotic in origin.

Unlike eukaryotic cells, bacterial cells do not have their DNA enclosed within a nuclear envelope and are referred to as prokaryotic cells.

Figure 1.9 Structure of prokaryotic cells

Prokaryotic cells typically have other differences from eukaryotic cells; most are surrounded by a thick, robust cell wall which allows them to survive in fluctuating environmental extremes of temperature, pH and dryness (Figure 1.9). A key feature of bacteria is that they are able to replicate incredibly fast. This allows huge populations to be generated in relatively short periods of time; in the human body this can have disastrous consequences, particularly if bacteria gain access to the blood.

Sepsis is often defined as an overwhelming life-threatening infection. It is more common than myocardial infarction (heart attack) and kills more people in the UK than breast, bowel and prostate cancer combined. Sepsis is more common in the very old and very young whose immune systems are in decline or not fully developed, while patients on immunosuppressive medications such as certain steroids are also at increased risk (Knight and Hore, 2018).

Symptoms of sepsis vary according to the age of the patient. According to the UK Sepsis Trust, the signs of sepsis in an adult include:

1 ‘Slurred’ speech or confusion

2 Extreme shivering or muscle pain

3 Passing no urine (in a day)

4 Severe breathlessness

5 It feels like you’re going to die

6 Skin mottled or discoloured.

In children, sepsis should be suspected if the child:

1 Is breathing very fast

2 Has a ‘fit’ or convulsion

3 Looks mottled, bluish, or pale

4 Has a rash that does not fade when you press it

5 Is very lethargic or difficult to wake

6 Feels abnormally cold to touch.

A child under five may have sepsis if he or she:

1 Is not feeding

2 Is vomiting repeatedly

3 Has not passed urine for 12 hours.

(UK Sepsis Trust, 2019)

Since sepsis is life-threatening and so common, it is essential that nurses learn to recognise some of the key features of this medical emergency early in their training. To help develop your knowledge, read through Mary’s case study.