integumentary system
skin, hair, nails and sweat glands
main functions of the skin
- Protection
- Thermoregulation
- Cutaneous sensation (touch)
- Excretion
- Absorption
- Vitamin D synthesis
drugs administered transdermally/topically may include:
- Nicotine (transdermal patches)
- Clotrimazole (anti-fungal medication)
- Lidocaine (local anaesthetic)
Respiratory System
- lungs in thoracic cavity protect by thoracic cage
-lung rests on daphragm - each lung has a hilus which brinchi passes.
- pulmonary arteries and veins carry blood from and to the heart
Cardiovascular System
moves oxygenated blood from the heart, to the different areas of the body,
Rectal administration
- better bioavailability than oral route as it avoids the stomach and also first pass metabolism
- reduces side-effects such as gastric irritation, nausea, vomiting.
Gastrointestinal System
- as enteral administration of a drug (by mouth) is the most common, safest and most convenient method.
- Drugs passing through the oesophagus and entering the stomach are exposed to harsh environments and may be inactivated by the acidic gastric j
- upon absorption into the intestinal bloodstream, the blood is carried to the liver (NOT directly back to the heart) via the hepatic portal system, and so drugs are subject to first-pass metabolism.
hepatic portal system
- blood drains from the intestines via the mesenteric veins, into the splenic vein, before moving across towards the liver as the hepatic portal vein.
Renal System
kidneys and ureters, with a single urinary bladder and urethra.
Nervous System
- brain and spinal cord
- surrounded and protected by the meninges,
- dura mater, the arachnoid and the pia mater).
Blood-brain barrier (BBB):
- tightly-connected endothelial cells in BBB ensure substances capable of passing through the endothelial capillary cells, or which are actively transported, can cross into the central nervous system.
- Lipid-soluble drugs can cross readily
- whereas polar or ionised drugs cannot. These rely on an active transporter syst
Cerebrospinal fluid
- is a clear colourless liquid found in the brain and spinal cord;
- acts as a cushion/buffer for the cortex providing protection of the brain inside the skull;
- contains small amounts of protein, glucose and potassium;
- contains relatively large amounts of sodium chloride;
- has no cellular components;
- is produced within the brain;
- can be sampled to aid diagnosis of certain conditions (e.g. meningitis);
- maintains its own pressure, which can be measured to diagnose or treat illne
endocrine System
glands and tissues
producing the hormones which regulate metabolism, growth, sexual function. Reproduction and sleep, amongst many other functions
Epithelial tissue
- Physical protection: from dehydration, biochemical degradation physical damage prevents penetration of bacteria, solvents, chemicals.
Glandular tissues
Endocrine glands secrete hormones into surrounding interstitial fluid,
diffuse in blood so influencing cell functions throughout the body.
-Such glands include the thyroid, pancreas and thymus and the endocrine cells which are scattered in the gastrointestinal tract.
Endocrine glands are also called “ductless glands”, as their secretory products enter the blood stream without the need for ducts.
Exocrine glands
produce secretions that travel through a duct to be released onto an endothelial surface.
tears, sweat and breast milk. They release their secretions via the process of exocytosis, eg sweat glands - known as a merocrine secretion.
apocrine secretion
when the apical side of each cell buds and splits from the main cell, taking a large proportion of the cytoplasm with it
skeletal muscle
very thin,
extremely long ) myocytes referred to as muscle fibres. Each fibre consists of several cytoskeletal filaments of actin (thin filaments) and myosin (thick filaments), arranged in repeating bands known as sarcomeres.
Once a signal to contract is received, myosin proteins pull on the actin filaments, causing a temporary shortening in the length of the overall fibre (this is known as the sliding filament theory of muscle contraction).
alternating arrangement of actin and myosin is striated.
Each distinct muscle fibre is wrapped in a layer of collagen and bundled together with many other fibres in a fascicle, many of which in turn are bundled together to form individual muscles, which in turn are connected to tendons, connected to the skeleton. Skeletal muscles contract only on receiving a voluntary nervous signal, and are referred to as striated voluntary muscle.
cardiac muscle
very limited ability to divide, so repair following injury is less than perfect. Myocardiocytes are striated with actin and myosin filaments,
contain a single nucleus and are much shorter than skeletal muscle cells.
well connected to each other, visible as a branched arrangement of cells joined with intercalated disks. This is important, as when the heart pumps blood around the body, contraction relies on, pacemaker cells to set a rhythm, hence this tissue type is referred to as striated involuntary muscle.
Smooth muscle
hollow organs such as the bladder, the respiratory, gastrointestinal and reproductive tracts and in the walls of blood vessels. smooth muscle cells do contain actin and myosin, they are arranged differently and hence do not appear striated.
Bone
made up of a flexible collagen-fibre matrix, filled in with a hard mineral substance called hydroxylapatite.
has rigidity and strength, but the flexibility afforded by the collagen matrix means that the bone is not brittle.
blood
ADME
absorption
Distribution
metabolic
excretion
