Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 49

1 DNA is found wrapped arounda) Histamineb) Histone proteinc) Myosin proteind) Keratin protein

2 The region of a cell primarily involved in protein synthesis isa) The smooth endoplasmic reticulumb) The lysosomesc) The plasma membraned) The rough endoplasmic reticulum

3 The diploid number of human chromosomes isa) 46b) 23c) 48d) 52

4 Release of energy within the mitochondria in the presence of adequate oxygen is referred to asa) Anaerobic respirationb) Aerobic respirationc) Glycosylationd) Gluconeogenesis

5 Which of the following is not a function of the Golgi apparatus?a) Production of lysosomesb) Preparing material for export out of the cellsc) Refining of crude proteins from the rough endoplasmic reticulumd) Production of mitochondria

6 Which of the following commonly results in dehydration?a) Vomitingb) Poorly controlled diabetesc) Not drinking enough fluidd) All of the above

7 Cells will show crenation when placed in aa) Hypertonic solutionb) Isotonic solutionc) Hypotonic solutiond) All of the above

8 Water intoxication can cause death becausea) Soft organs will rapidly become dehydratedb) Swelling of the brain raises the intracranial pressure, reducing blood flowc) Excess water increases movement of water into the bloodd) Blood pressure will rise rapidly

9 The elastic tissue found lining the bladder isa) Simple columnar epitheliumb) Simple cuboidal epitheliumc) Pseudostratified epitheliumd) Transitional epithelium

10 Which of the following tissues forms the walls of each alveolar air sac?a) Stratified columnar epitheliumb) Stratified cuboidal epitheliumc) Simple squamous epitheliumd) Simple cuboidal epithelium

Chapter summary

Human cells have three major regions called the nucleus, the cytoplasm and the plasma membrane. The nucleus is the control centre of the cell and is the location of DNA. When cells divide the DNA condenses to form chromosomes, which can be visualised and counted. Human cells (with the exception of sperm and ova) have the diploid number of chromosomes (46). Deviations from this diploid number can result in chromosomal disorders such as Down’s syndrome.

The cytoplasm of the cell consists of the rough endoplasmic reticulum which is an area of protein synthesis and the smooth endoplasmic reticulum which is responsible for the synthesis of lipids (fats). The cytoplasm is also the location of organelles including: mitochondria which release energy from molecules such as glucose and the Golgi apparatus which prepares and packages material for export.

The plasma membrane which surrounds the cell is composed predominantly of a phospholipid bilayer in which there are a variety of proteins which function as channels and receptors. The plasma membrane holds the cell together, controls what enters and leaves the cell and plays key roles in signalling and recognition between cells.

Cells are grouped together in organised collections termed tissues; these include epithelial, connective, muscle and nervous tissue which are used to construct the internal and external organs. The human body also hosts a diverse community of microorganisms which are collectively referred to as the microbial biome.