5: Organ Systems Flashcards
What is the integument system?
The term integument system is used to describe the skin and its associated structures. Eg: hair, nails, glands
It’s the largest organ of the body
What is the role of the integument system?
The role of the integument system is to form a boundary between our internal and external environment. It prevents death by infection, water loss and heat loss
It’s major roles are: protection, temperature regulation, sensory perception, metabolism and waste disposal
Explain the integument system’s role of protection:
The integument system separates internal and external environments and protects the body in three main ways:
- Physical barrier
- Chemical barrier
- Biological barrier
How does the integument system work as a physical barrier?
The integument works as a physical barrier because the protein keratin in the skin’s surface and the skin cell’s secretions makes skin waterproof. Connective tissues make it durable and flexible
How does the integument system work as a chemical barrier?
The integument works as a chemical barrier because skin secretions are acidic and antibacterial so retard bacteria growth. Melanin in skin cells shields from UV radiation
How does the integument system work as a biological barrier?
The integument system works as a biological barrier because cells of the immune system live within the skin. They recognise foreign bodies and organisms (called antigens) that are invading and destroy them. This helps in the destruction of viruses and bacterias
Explain the integument system’s role as a temperature regulator:
The skin is an integral component of the homeostatic mechanisms that monitor and regulate the body’s temperature so that it can work most effectively within its narrow temperature range
Explain the integument system’s role in sensory interaction with the environment:
The skin contains sensory receptors that respond to light touch, deep pressure, displacement of the hair shaft and free nerve endings that detect temperature changes and excessive forces that cause pain
Explain the integument system’s role in metabolic functions:
Sunlight acts on modified cholesterol molecules in the dermal blood vessels. This converts them into vitamin D to be used elsewhere in the body
Explain the integument system’s role in excretion:
The integument system eliminates nitrogen containing wastes from the body in the form of sweat, which also loses water and salts, which have to be replaced by dietary intake
What is the structure of the skin?
The skin is pliable, tough, stretchable, waterproof and self-repairing. It is made up of keratinised stratified squamous epithelium
The skin has two main layers: the outer epidermis and inner dermis, with the hypodermis beneath
Within the body’s orifices, the skin is un-keratinised
What is the structure of the epidermis?
The epidermis is mainly keratinised stratified epithelium. Over most parts of the body is thin skin, which has four layers. On the fingertips, palms and soles of the feet there is an extra layer
The non-keratinised skin is more uniform, with surface layers still alive (unlike keratinised epidermis). This is found in specialised tissues and is kept from drying out by a variety of secretions
What are the layers of thin skin?
The layers within thin skin are:
- Stratum corneum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
What are the layers of thick skin?
Thick skin has the same four layers as thin skin: 1. Stratum corneum 2. Stratum granulosum 3. Stratum spinosum 4. Stratum basale PLUS 5. Stratum lucidum
What are the cell types and their roles in the epidermis?
The four cell types in the epidermis are:
- Keratinocytes (the majority type)
- Melanocytes (skin pigmentation)
- Merkel cells (skin sensation)
- Langerhans’ cells (immune cells)
What is the structure of dermis?
Dermis is the innermost component of the skin and is tough and leathery
It is made of dense irregular connective tissue and is strong and flexible
What are the components of the integument within the dermis?
There are 5 components of the integument within the dermis:
- Blood vessels
- Nerves
- Sweat glands
- Sebaceous glands
- Hair
What are the roles of nerves within the dermis?
Within the dermis, nerves are used for sensory and motor activities
What are the roles of sweat glands within the dermis?
Sweat glands can be eccrine glands (sweat first) and apocrine glands (begin to excrete from puberty)
What are the roles of sebaceous glands within the dermis?
Within the dermis, sebaceous glands secrete an bactericidal oil called sebum to soften and lubricate the hair and slow water loss from the skin
Sebaceous glands are simple alveolar glands regulated by hormones
What is the role of hair within the dermis?
Within the dermis, hair is produced by follicles that extend from the epidermal surface deep into the dermis
What is the definition of the digestive system?
Th digestive system is a number of structures that carry out the tasks involved in gaining nutrients. AKA gastrointestinal system
What is the role of the digestive system?
The digestive system carries out a number of tasks involved in gaining nutrients from digested food:
- Ingestion
- Digestion
- Absorption
- Egestion
What is ingestion?
Ingestion is the taking in of food
What is digestion?
Digestion is the breaking down of ingested food into its component molecules
What is absorption in the digestive system?
Absorption is the extraction of nutrients from digested food
What is egestion?
Egestion is the system of disposing of waste from digested food
What are the different types of nutrients?
Nutrients can be placed into the following categories:
- Carbohydrates
- Proteins
- Fats and lipids
- Vitamins
- Minerals and trace elements
- Salts
What are carbohydrates?
Carbohydrates are a nutrient that provide an energy source for the human body
What are proteins?
Proteins are a nutrient that can be used to build cells and tissues in the human body
What are fats and lipids?
Fats and lipids are proteins with many uses in the human body: for example in hormone production
What are vitamins?
Vitamins are a nutrient that cannot be made by the human body and so must be extracted from food
What are minerals and trace elements?
Minerals and trace elements are nutrients that are used in the assembly of different structures in the human body
What are salts?
Salts are a nutrient that is fundamental to all cells in the human body
What are the components of the digestive system?
Components of the digestive system include:
- Oral cavity
- Tongue
- Oesophagus
- Liver
- Gallbladder
- Colon
- Appendix
- Anal canal and anus
- Stomach
- Pancreas
- Jejunum
- Rectum
What are the components of the mouth/ buccal cavity within the digestive system?
The components of the mouth/ buccal cavity that play a role in the digestive system are:
- Teeth
- Buccal lining
- Tongue
- Salivary glands
What is the role of teeth within the digestive system?
The role of the teeth within the digestive system is to masticate food. The muscles in the tongue, cheek and lips form a bolus from the food
What is the role of the buccal lining within the digestive system?
The buccal lining is a thick layer of un-keratinised stratified squamous epithelium. It has a high cell turnover rate to cope with the friction from chewing food
What is the role of the tongue within the digestive system?
The tongue is a mainly muscular structure. It is where the tastebuds are found
What is the role of the salivary glands within the digestive system?
There are three main sets of salivary glands: the parotid, sub-mandibular and sub-lingual. They all secrete saliva into the buccal cavity which serves a number of roles:
- Cleanses the mouth
- Dissolves food chemicals so they can be tasted
- Moistens food with mucin and water to help compact it into a bolus
- Contains enzymes that begin food digestion. Eg amylase and lipase
What is the role of the oropharynx and laryngopharynx within the digestive system?
These structures are made of epithelium tissue and rich in mucous glands, which smooths the passage for the food bolus which has entered from the mouth
The skeletal muscles in the walls of these structures run longitudinally and circumferentially to propel food into the oesophagus
What is the swallow reflex?
The swallow reflex is a complex and controlled event that allows food to access the oesophagus
What is a reflex peristalsis?
Once the swallow reflex allows food into the oesophagus, the reflex peristalsis takes over and propels food into the stomach
Describe the positioning of the oesophagus:
The oesophagus is a muscular tube about 25cm long. It runs through the diaphragm at the oesophageal hiatus and joins the stomach at the cardiac orifice where there is a smooth muscle sphincter which is closed, except for when food arrives
Describe the structure of the oesophagus:
The oesophagus is made up of the following:
- Serosa
- Muscularis
- Sub-mucosa
- Mucosa
What is the serosa?
The serosa is a connective tissue membrane that surrounds the oesophagus tube as its outermost layer
What are muscularis?
Muscularis are skeletal muscles running in different directions as the second most outer layer of the oesophagus
What is the sub-mucosa?
The sub-mucosa is a connective tissue layer beneath the muscularis