Physiology Flashcards
What is ATP?
A general source of energy for all intracellular metabolic reactions
What are arterioles?
Blood vessels that are smaller than the arteries and that branch from arteries with variable amounts of elastic and smooth tissue
What is atrophy?
Reduction in size
What is autoregulation?
The process by which tissue perfusion remains relatively constant despite blood pressure changes
What are baroreceptors?
Receptors that are sensitive to pressure, and located in the aorta, internal carotid arteries and other large arteries in the neck and chest
What are capillaries?
Small blood vessels that join arterioles and venules, and are present in almost every tissue in the body
Define Cardiac Output (CO)
The volume of blood ejected by one ventricle into its respective artery each minute.
Calculated as the heart rate multiplied by the stroke volume
What are chemoreceptors?
Sensory receptors that detect the presence of a specific chemical
Define diffusion
The simple, passive movement of a substance down a concentration gradient
What is endocardium?
Cardiac tissue that consists of three layers and is continuous with the endothelial lining of the large blood vessels attached to the heart
What is endoplasmic reticulum?
Organelles that forms a network of membranes within the cell
Define facilitated diffusion
A process, faster than simple diffusion, with the passage of substances down their concentration gradients requiring a transporter
What is Golgi apparatus?
Membranous sacs that sort and modify proteins arriving from the granular endoplasmic reticulum, packing them into vesicles, before sending them to other organelles or secreting them
What are Golgi tendon organs (GTO)?
Bundles of collagen fibres, encapsulated by a connective tissue layer present at the muscle-tendon junctions
Define haemopoiesis
The formation of red blood cells in the bone marrow
Define haemostasis
Control of bleeding
Define heart rate (HR)
The number of ventricular contractions per minute
Define homeostasis
The maintenance of a constant internal conditions, within narrow limits, despite external changes
Define hyperplasia
An increase in tissue/organ size due to an increase in cell number
Define hypertrophy
An increase in tissue/organ size due to an increase in cell size
What are inotropes?
Substances that affect the force of cardiac contractility
What are lysosomes?
Single-membraned oval organelle containing highly acidic digestive enzymes that break down bacteria, cell debris and dead organelles
What is messenger RNA (mRNA)?
RNA that carries genetic code from the nucleus to the cytoplasm
What are mitochondria?
Double-membraned, elongated, ovoid structures that function to make energy available to cells in the form ATP
What are motor units?
Each skeletal muscle fibre is innervated by a single motor neurone, which comprises a motor neurone and all the muscle fibres it innervates
Define innervation
- To supply an organ or body part with nerves.
2. To stimulate a nerve, muscle or body part to action
What are muscle spindles?
Organs that lie parallel to the skeletal muscle fibres, and measure the extent of muscle stretch
What is myocardium?
Tissue that consists of cardiac muscle cells (myocytes), which are responsible to for cardiac contractability
What are myofibrils?
Filamentous bundles on the individual muscle fibre that run along the entire length of the fibre
Define myocytes
Muscle cells
What is a nuclear membrane/envelope?
Two membrane surrounding the nucleus containing pores that regulate the entry and exit of molecules
What are nucleoli?
Highly coiled structures not enveloped by a nuclear membrane and containing RNA and protein components
What is the nucleus?
The control centre of almost all cells
Define ossification
The conversion of fibrous tissue or cartilage into bone.
Can either be intramembranous or endochondrial
What is the pericardium?
The fibrous sac covering the whole heart
What are peroxisomes?
Single-membraned, oval organelles that destroy the highly toxic hydrogen peroxide (H2O2) that is produced by certain cell reactions
What are ribosomes?
Organelles composed of about 70 proteins and several RNA molecules
There are two different subunits of different sizes, 30s and 50s, with the former being smaller
What is ribosomal RNA (rRNA)?
The length of RNA where the protein molecules are actually assembled
What is a sarcomere?
A muscle fibre matrix where the myofibrils are suspended
What is sarcoplasmic reticulum?
An endoplasmic reticulum equivalent in the muscle fibre.
Runs longitudinally along the myofibrils and wrap around groups of myofibrils
What is the sinoatrial node?
The part of the heart that causes the pacemaker potential
What is stroke volume (SV)?
Volume of blood ejected in one ventricular contraction
Define total peripheral resistance (TPR)?
Resistance to blood flow in the circulatory system
Define transcription
mRNA transcription
What is transfer RNA (tRNA)?
RNA that transfers amino acids to the ribosomes to manufacture proteins
Define translation
The formation of proteins from the mRNA
Define transmural pressure
The pressure across the wall of a vessel
Can be affected by external and internal pressure
What are venules?
Vessels that collect the blood from the capillaries and transport it to the veins
