Introduction Flashcards
What is physiology ?
The study of the normal functioning of living organisms
Why do we learn about physiology ?
• Dental anaesthesiology
• Sedation
• Medical diagnosis
What are the 4 major classes of tissues ?
- epithelia - protection, secretion and absorption
- connective tissue - structural support
- muscle - for movement
- nervous tissue - communication, coordination and control
Summarise the musculoskeletal system
Contains bones, joints and attached muscles
Important for movement, protection and support of other tissues
Summarise the nervous system
Involved in rapid coordination of body activities via nerve impulses
Involved in responding to stimuli and important for memory
Summarise the cardiovascular system
Involved in the circulation of blood to carry things around the body
Important in distributing heat and assisting temperature control
Summarise the respiratory system
Important in exchanging oxygen and carbon dioxide between the body and atmosphere
Summarise the digestive system
Involved in absorbing nutrients and absorbing and conserving water
Summarise the urinary system
Involved in the elimination of metabolic waste, regulation of volume and composition of bodily fluids
Summarise the endocrine system
Involved in the slower regulation of body activities and other organ systems by circulating hormones
Summarise the reproductive system
Involves sperm, ova, fertilisation, pregnancy and birth
Summarise the immune system
It protects against microbes, infection and parasites
It rejects foreign tissue
Summarise the Integumentary system
(Note - this is the skin)
It protects against environmental hazards and helps to regulate body temperature
It also provides sensory information
What is cell physiology ?
It considers events at chemical and molecular levels within and between cells
What is systems physiology ?
It considers all aspects of the function of specific organ systems
What is integrative physiology ?
It is how the human body responds to internal and external stimuli
What is pathophysiology ?
It is the study of the effects of diseases on organs and organ system functions
What are the fluid compartments of the body ?
Intracellular fluid - fluid inside the cells
Extracellular fluid - fluid outside the cells (blood plasma and interstitial fluid)
Why are the fluid compartments important ?
Because in order for cells to live and function they must be surrounded by an aqueous environment
- the composition and conditions of the interstitial fluid need to be kept pretty constant in order for cells to survive
How is constancy of the extracellular fluid maintained ?
Things are added or removed by :
• respiratory system - transports oxygen from the external environment to plasma and carbon dioxide in the opposite direction
• digestive system - transfers nutrients from the external environment into plasma
• cardiovascular system - distributes nutrients and oxygen throughout the body and removes carbon dioxide to the lungs and waste products to the liver and kidneys
• urinary system - controls the concentration of electrolytes in the ECF and removes metabolic waste products
What is homeostasis ?
The maintenance of a relatively stable internal environment
Who discovered the concept of homeostasis ?
Claude Bernard in 1865
List some of the conditions of the internal environment controlled by homeostasis
- osmolarity
- electrolyte concentrations
- pH
- oxygen and carbon dioxide levels
- concentration of nutrient molecules
- concentration of metabolic waste products
- temperature
Summarise the importance of keeping osmolarity constant
Cells are essentially fluid filled bags which can swell and burst or shrivel up if external osmolarity changes too much e.g. by taking ecstasy or drinking too much water after a marathon
Summarise the importance of keeping electrolyte concentrations constant
Electrolytes perform a variety of vital functions e.g. A rhythmic heart beat depends on a tight range of [K+] in the ECF
Summarise the importance of keeping pH constant
Changes in pH affect enzyme activity and neurone function
Summarise the importance of keeping oxygen and carbon dioxide levels constant
Oxygen is important in respiration to make ATP to power biochemical reactions and carbon dioxide increases acidity so needs to be removed
Summarise the importance of keeping the concentration of nutrients constant
Cells need a constant supply of nutrients e.g. glucose for energy production which is needed for life sustaining activities
Summarise the importance of keeping the concentration of metabolic waste products constant
Cells excrete waste products into the ECF and if not removed they can accumulate and become toxic
Summarise the importance of keeping temperature constant
Body cells can only function within a narrow temperature range
What are the 3 things that homeostatic control systems must be able to do ?
1) detect changes that occur
2) integrate this with other relevant info
3) make appropriate adjustments to restore the change back to normal
What are the 2 types of control systems ?
Intrinsic control systems - within a particular organ
Extrinsic control systems - outside an organ and these coordinate regulation of several organs towards a common goal
What are the components of physiological control systems ?
- sensors/receptors - these pick up information and monitor what is being controlled
- control centre - where the information is processed
- effectors - these bring about responses
How are the components of the control system linked ?
They are linked by communication pathways.
Afferent pathways link sensors to the control centre
Efferent pathways link the control centre to effectors
Give 2 examples of homeostatic control systems
- regulation of body temperature
- regulation of blood glucose
(These are both negative feedback loops)
Summarise the slow communication pathway
These involve the transmission of a chemical messenger or hormone to distant sites via blood and diffusion
Summarise the rapid communication pathway
It uses the peripheral nerves to transmit information rapidly by way of nerve impulses to and from the CNS
