Lecture 1 Flashcards
What is physiology?
Study of:
- purposeful interactions of matter energy and fields in a living system
- interactions are functional
- dynamic - movement in an organised way
- flow requires control and regulation
Example were ‘flow’ occurs in the living body
- Pulmonary system
- Cardiovascular system
- GI system (e.g. if too fast, can suffer from diahorrea, if too slow, can suffer from constipation)
- renal system
etc
Explain how flow is used in the pulmonary system? Why is flow needed? Does it overlap with other system? Where does flow occur?
o Enable Respiratory Gas Flow
o Supply of O2 /Removal CO2 matched to Physiological Demand
o Flows through Trachea - Bronchial Tree to Alveoli
o Transfer Matched to Cardiovascular Flow
o Increased Demand - Increased Flow
How to measure disease and disturbance to pulmonary flow? How is healthy flow determined?
o Lung Capacity (Volume)
o Peak Expiratory Flow Rate
o Airway Resistance
How can these indicate disease (flow - pulmonary system)
o Lung Capacity (Volume) decrease
o Peak Expiratory Flow Rate decrease
o Airway Resistance increase
What do drugs commonly want to improve?
Flow
Capacity
Explain how flow is used in the cardiovascular system
o Supply of O2 /Removal CO2
o Supply of Nutrients supporting Metabolism /Growth/Renewal - Removal of Waste Products
o Flow/Supply matched to Physiological Demand
o Flows Heart /Lungs - Arteries – Arterioles – Capillaries –Venules –Veins
o NB – Pulmonary Flow matched to Cardiovascular Flow
o Increased Demand - Increased Flow
How can you measure flow in cardiovascular system?
o Electrocardiogram (ECG) - Pump o Heart Rate x Stroke Volume = Cardiac Output o Blood Pressure o Blood Biochemistry (Cholesterol + Flow Factors)
Examples of disturbance to normal cardiovascular flow
Coronary heart disease - heart’s blood supply is blocked or interrupted by a build-up fatty substances in coronary arteries
What have of these systems got to do with cell physiology?
- Huge range of Membrane Transporters/Channels selectively regulating flow
- Nerve Action Potential precise spatio-temporal control of Na+ /K+ current - electrochemical flow
Connection between potential energy and kinetic energy
(blank)
Potential energy - what is this?
- Energy in ‘Stored Form’
- Can be Released and Harnessed to Perform ‘Work’ • It is called ‘Potential’ because it is not being used
- Body has huge reserves of PE re
Kinetic energy - what is this?
- Called ‘Kinetic’ as it is associated with Movement
- Energy made into movement of matter– considered as ‘Work’
- Body continually utilises and directs KE in a highly controlled way
Give some examples (some from this list) of potential energy in physiological systems
- PE stored in Chemical Bonds – Energy Released in Reaction
- PE in the ~Pi bond in ATP universally used as currency for delivery of Energy
- PE in Concentration Gradients across Cell Membranes
- PE in Electrochemical Gradients - 1 Generates Membrane Potential
- PE in Electrochemical Gradients - 2 The PE Source for 2o Active Transport
- PE in Electric Fields – ‘Action at a Distance’ on Voltage Sensitive Proteins
- ‘Elastic PE’ – Held in Molecular Structures For Release as Mechanical Energy
- The release of PE needs to match the demand for KE – Again Flow Control
Give some examples (some from this list) of Kinetic energy
- Chemical Bond -> Thermal Energy from exothermic reactions -> Random Brownian Motion (‘disorganised’ flow)
- Chemical Gradient -> Molecular Movement across Membrane
- Electrochemical Energy Gradient - 1 -> Current Flow across Membrane
- Electrochemical Energy - 2 -> Current Flow + Co-Transport secondary Active Transport
- Electrical Field -> Field Movement + Conformational Changes
- Elastic Energy -> Mechanical Energy
- > Conformational Changes -> Macromolecular Movement
Chemical bond PE can lead to KE due to heat being released
PE: Concentration gradient across membrane
KE: Diffusion of molecules across membrane
What is the correct name for the ‘sodium postassium pump’
Na+/K+ ATPase
How is the Na+/K+ ATPase involved in potential energy and kinetic energy…?
• Na+ /K+ ATPase is an enzyme coupled transporter at the heart of Cell Energetics.
• At rest uses 30-35% of Cellular ATP
• Uses Chemical Bond PE in ATP - enables conformational change in ATPase (Chemical Bond
-> Elastic Energy -> Mechanical Energy)
• Carries 3 Na+ out / 2K+ into the Cell
• This is Electrogenic - contributes to an Electrochemical Gradient across the Cell
• E. Chem. Gradients –V. important PE Source
• E.Chem. Gradients have an associated Electric Field – a further source of PE
• Electric Fields allow ‘Action at a Distance’
Electrochemical gradient PE and Electrochemical current flow KE
Electrical field PE -> Ions move KE
How can potential energy be added to a molecular structure?
‘Elastic’ Energy Stored in ‘Stressed Molecular’ Structure
• Proteins ability to switch between conformational shape underpins much function.
• Potential Energy added by phosphorylation ~ Pi to add ‘Elastic PE’ to attain new higher energy conformational state
• Elastic energy is released as Mechanical Movement when it ‘springs back’ to the lower energy conformation.
• Property underpins PE storage in proteins
Elastic energy (PE) -> Mechanical energy (KE)
How is physiology classified?
Characterised by the close control of the flow and interplay of work and information