L1 Cell Physiology Flashcards
What’s physiology?
Study of life
Specifically how cells, tissues, organs and whole organisms function
Emphasis on purpose (why) and mechanical (how)
Anatomy v. Physiology
Anatomy is structure/function relationship
Anatomy supports the purpose (why) of physiology
Functional organization of body
Chemical Cellular Tissue Organ Body system Organism
Four tissues of organs
Epithelial
Connective
Muscle
Nervous
Three main functions of anatomical/physiological systems
Facilitate survival of individual
Facilitate survival of species
Coordinate functioning
What’s homeostasis?
Ability to maintain a relatively stable internal environment in an ever-changing outside world
Pyrogens
Cause a rise in the setpoint for metabolic heat production
Exogenous pyrogens
From foreign substance
i.e. bacteria or virus
Endogenous pyrogens
Produced by immune cells in response to infection
Increase temp to try to kill bacteria
Homeostatic control systems must be able to
Detect
Integrate
Restore
Negative feedback system
Primary type
Maintains stability by defending set points
Opposes initial change
Negative feedback components
Sensor
Integrator
Effector
Negative feedback components in temperature regulation
Sensors - skin
Integrator - hypothalamus
Effectors - vasodilation, sweating, panting
Vasoconstriction, shivering, non shivering, thermogenesis
Thermoneutral zone
Small range of temperature where the body temp will remain constant
Out of that range, metabolism will have to work to cool down or warm up
Larger tolerance to cold temps
About 10 degree range
Blood glucose levels: negative feedback
Normal blood glucose level 90mg/100mL
Sensor - pancreas
Integrator - pancreas
Effector - peripheral cells
Regulation of hormone release by hypothalamic-pituitary axis (HPA)
Hypothalamus releases hormones
Anterior pituitary releases tropic hormones
Target organ/gland releases peripheral hormone
Released hormones negatively feedback to hypothalamus and anterior pituitary to stop this loop
Hypothalamus releases what to anterior pituitary?
Corticotropin releasing hormone
CRH
Anterior pituitary releases what to adrenal cortex?
Adrenocorticotropic hormone
ACTH
Adrenal cortex releases what hormone?
Cortisol
CORT
Addison’s Disease
No CORT
High CRH
High ACTH
Secondary adrenal insufficiency
Low ACTH
Low CORT
High CRH
ACTH stimulation test
Can help distinguish between Addison’s and secondary adrenal insufficiency
Metastatic rumor/infection
Nothing works in HPA axis
Positive feedback system
Amplifies an initial change
Change in same direction until completion of event
Uterine contractions
Lactation
Urination
Defecation
When things are expelled from body
Feedforward
Anticipatory changes
Smelling dinner leads to salivation and growling stomach
Sprinter getting ready to run a race and his heart and respiratory rate rise
Disruption in homeostasis of any “vital” parameter can lead to
Illness and death
