Physiology of human cells 1

Question 1

Define physiology

Answer 1

The branch of biology that aims to study and understand the mechanisms of living things from the ionic and molecular level to the integrated behaviour of the whole body and the influence of the external environment

Question 2

What does this help us achieve

Answer 2

o Understand the basics of our bodily health
o How it responds to and adapts to everyday challenges
o The adverse effects of diseases which help us establish guidelines and develop treatments for human and animal health
o This combination of molecular, cellular systems is what sets physiology apart from other sciences

Question 3

what tissues are covered in this course

Answer 3

o Muscle
o Nervous
o Epithelial
o Connective

Question 4

what organs are covered in this course

Answer 4

o Lung
o Brain
o Heart
o Kidney
o Stomach
o Colon

Question 5

what organ systems are covered in this course

Answer 5

o Nervous
o Endocrine
o Immune
o Circ
o Muscle/skeletal
o Integument (skin hair nails and exocrine)
o Respiraotry
o Urinary
o Digestive
o Reproductive

Question 6

what is homeostasis

Answer 6

Homeostasis is the process by which the body reacts to changes in order to keep conditions inside the body like temperature at the same optimal level through cooperation and interdependance of cells body systems and organs to get to homeostatic range

Question 7

what does homeostasis help us achieve

Answer 7

the state of steady internal, physical and chemical conditions maintained by living systems; It’s the condition of optimal functioning for organisms and includes body temp, fluid balance etc. being kept within pre-set limits called homeostatic range

Question 8

what factors can homeostasis include

Answer 8

o Conc of nutrient molecules
o Conc of CO2 and O2
o Conc of waste products
o pH
o Conc of water, salt and other electrolytes
o Temperature
o Volume and Pressure

Question 9

What is the homeostatic ocntrol system

Answer 9

the functionally interconnected network of body components that operate to maintain a given physical or chemical factor in the internal environment relatively constant around an optimal level

Question 10

what are the two types of HCS

Answer 10

Intrinsic (local) controls are inherent compensatory responses of an organ to a change
Extrinsic controls are responses of an organ to factors outside like the nervous and endocrine systems

Question 11

What are the two types of HCS responses

Answer 11

positive and negative feedback

Question 12

what is positive feedback

Answer 12

Output is continually enhanced or amplified so that the controlled variable is moved in the direction of the initial change or a pathway in which the response reinforces the stimulus and only stops after a drastic change or change of state

Question 13

What is negative feedback

Answer 13

Change in a homeostatic control factor triggers a response that seeks to restore the factor to normal by moving the factor in the opposite direction of its initial change; it is a pathway where the response opposes the signal

Question 14

what are the key components of a feedback system

Answer 14

 Sensor- specific to variable needing to be controlled
 Set point- reference point for sensor to compare against
 Effector- if sensor isn’t equal to set point, error signal produced to activate effectors to restore variable to desired level

Question 15

define set point and dynamic range and how they relate

Answer 15

o Set point is the optimal point where our systems are at maximum efficiency
o Dynamic range is the margin of error above or below the set point where conditions allow us to still operate but not at maximum efficiency
this can be altered by training or exposure to environments and stimuli

Question 16

what are the limitations of negative control

Answer 16

 Feedback control is initiated after variable has been disturbed
 Amount of correction is applied and assessed by magnitude of error signal causing incomplete correction
 Overcorrection which is where an error signal causes inverse of stimulus to occur due to too much control application causing oscillations; These are overcome by multiple regulatory mechanisms

Question 17

what is thermoregulation? how does it happen?

Answer 17

o The process in which the body achieves homeostasis by returning body temp to optimal levels
 Too hot–>sweat
 Too cold–>shiver

Question 18

what are the two types of thermoregulatory responses

Answer 18

Voluntary like clothing changes, nutrition, resting
Involuntary like sweating and shivering and hair raising

Question 19

how is positive feedback different from negative feedback in terms of the set point?

Answer 19

o Negative feedback means error signal results in reduced deviation from set/reference point
o Positive feedback means error signal increases deviation from set/reference point resulting in a vicious cycle

Question 20

give examples of Positive feedback

Answer 20

Labour where oxytocin is released from hypothalamus increasing uterine contractions and baby’s head is pushed through stretching cervix and causing larger oxytocin release

Rising of action potential is when depolarisiation happens opening Na channels, the entrance of which cause further depolarization (positive feedback loop) which stops after a change of state where Na channels deactivate

Question 21

what is a feedforward mechanism?

Answer 21

o Brings a compensatory response in anticipation of a change in a regulated variable like mouth watering and gastric secretions to the thought/smell of food

Question 22

what is an anticipatory change

Answer 22

eg. Changes in renal function in preparation for changes brought on by food intake resulting in changes in concentration of ions in the plasma that will need to be controlled within physiological rang