Wk 1 - Cell adaptation, Injury & Death.pdf

Wk 1 - Cell adaptation, Injury & Death Thursday, 15 February 2024 1:04 am Review - Cells and Tissue The human body is made of different cell types, which group together to form tissues....

Wk 1 - Cell adaptation, Injury & Death Thursday, 15 February 2024 1:04 am Review - Cells and Tissue The human body is made of different cell types, which group together to form tissues. Tissues make up organs, and organs work together in systems Ø Cell > tissue > organ > organ system > organism Cell structure and function The cells are the building blocks of life. They are the smallest living functional unit. They group together to make up our tissues, organs, organs systems and organism. Cells need oxygen, nutrients to survive. Cells remove waste such as cardon dioxide through respiration. Cells have specialised regions and organelles that perform many and different functions. Ø Cell membrane ○ semi-permeable barriers that is made up of a phospholipid bilayer with embedded transport proteins ○ Oxygen and carbon dioxide (respiratory gases) can diffuse across the membrane but ions (Na+) and larger molecules such as amino acids and glucose cannot. They require special transport proteins to cross the membrane. Ø Mitochondria ○ Singular form is mitochondrion ○ Is the site of major ATP production within the cell through a process known as aerobic cellular currency for cells and is used in many processes such as transport, chemical work and mechanical, e.g muscle contraction Ø Transport and storge vesicles Ø Lysosomes Ø Smooth endoplasmic reticulum Ø Rough endoplasmic reticulum Ø Golgi apparatus Ø Nucleus Cell energy □ Many cellular processed need energy. □ The energy currency of our cells is called Adenosine Triphosphate (ATP). □ The cells break down (metabolise) larger molecules to yield ATP which can then be used to power processes such as: ○ Active transport, chemical work and mechanical, e.g muscle contraction □ Cells use aerobic respiration (that is with oxygen) to produce ATP from glucose. □ Figure 1 (A) ATP structure (B) Aerobic respiration process with a cell: i. Glucose enters the cell via a transport protein ii. Glucose is split into 2 pyruvate molecules (glycolysis) § This process only yields 2 ATPs and is not very efficient but with the presence of oxygen, pyruvate molecules enter the mitochondria to produce many more ATP molecules. Body fluids and ion concentrations Ø Body fluids □ There are 2 main fluid compartments in the body: § Intracellular fluid (ICF) which is contained within our cells § Extracellular (ECF), other fluids that is not inside the cells but outside the cells but also in the internal environment such as: □ Intravascular (plasma) □ Interstitial (between cells) □ Transcellular, such as synovial fluid ( fluid within a joint space), urine, pleural fluid (fluid found between the layers of the pleura, pleura is the membrane that line the thoracic cavity and surround the lungs) □ Little note: § Intra= within or inside § Inter= between § Trans= across Ø Ion concentration □ Ions are not equally distributed across the ICF EFC, therefore the resulting concentration gradients are vital for normal cell function □ ATP is required to move ions against their concentration gradient □ The 3 most important ions and their concentrations in ICF and ECF are: § Sodium (Na+) □ ECF = 135-145 mmol/L □ ICF = 10-14 mmol/L □ Its concentration gradient is higher in ECF (outside the cell) § Potassium (K+) □ ECF = 2.5-5 mmol/L □ ICF = 140-150 mmol/L □ Its concentration gradient is higher in ICF (inside the cell) § Calcium (Ca2+) □ ECF = 8.5-10.5 mmol/L □ ICF =