Session 1- Human Body Flashcards
What is anatomy
Study of the structure of body parts and their relationship to one another
What is physiology
Study of the function of body parts, how they work to carry out life sustaining activities
Complementarity of structure and function
Function always reflects structure
What a structure can do depends on its specific form known as the principle of complementarity of structure and function
Levels of structural organisation
Chemical level- atoms combine to form molecules
Cellular level- cells are made up of molecules
Tissue level- tissues consist of similar types of cells
Organ level- organs are made up of different types of tissues
Organ system level- organ systems consist of different organs working together closely
Organismal level- human organism is made up of many organ systems
Requirements for life
Maintaining boundaries
Movement
Responsiveness
Digestion
Metabolism
Excretion
Reproduction
Growth
Maintaining boundaries
Separation between internal and external environments must exist
Plasma membranes separate cells
Skin separates organism from environment
Movement
Muscular system allows movement of body parts via skeletal muscles, of substances via cardiac muscle and smooth muscle
Responsiveness
Ability to sense and respond to stimuli
Withdrawal reflex prevents injury
Control of breathing rate, which must change in response to different activities
Digestion
Breakdown of ingested food, followed by absorption of simple molecules into blood
Metabolism
All chemical reactions that occur in body cells
Sum of all catabolism and anabolism
Excretion
Removal of wasted from metabolism and digestion
Urea from breakdown of proteins, CO2 from metabolism, faeces from unabsorbed foods
Reproduction
At cellular level, involves division of cells for growth or repair
At organismal level, reproduction is the production of offspring
Growth
Increase in size of body part or of organism
How many organ systems are there?
11
Integumentary system
Forms the external body covering, protects deeper tissues from injury
Synthesises vitamin D
Houses cutaneous receptors and sweat glands
Skeletal system
Protects and supports body organs
Provides a framework the muscles use to cause movement
Blood cels formed within bones
Bones store minerals
Muscular system
Allows manipulation of the environment, locomotion, and facial expression
Maintains posture and produces heat
Nervous system
Responds to internal and external changes by activating appropriate muscles and glands
Endocrine system
Glands secrete hormones that regulate processes such as growth, reproduction and metabolism by body cells
Cardiovascular system
Blood vessels transport blood which carries oxygen, CO2, nutrients, wastes
Heart pumps blood
Lymphatic system
Picks up fluid leaked from blood vessels and returns it to blood
Disposes of debris in the lymphatic stream
Houses lymphocytes involved in immunity
Immune responses mounts the attack against foreign substances within the the body
Respiratory system
Keeps blood constantly supplied with oxygen and removed CO2
The gaseous exchanges occur through the walls of the air sacs of the lungs
Digestive system
Breaks down for into absorbable units that enter the blood for distribution to body cells
Indigestible foodstuffs are eliminated as faeces
Urinary system
Eliminates nitrogenous wastes from body
Regulates water, electrolyte, acid-base balance of the blood
Male reproductive system
Production of offspring
Testes produce sperm, male sex hormones
Male ducts and glands aid in delivery of sperm to female reproductive tract
Female reproductive system
Production of offspring
Ovaries produce eggs and female sex hormones
Remaining structures serve as sites for fertilisation and development of the foetus
Mammary glands of female breasts produce milk to nourish the newborn
How do nutrients and waste pass between blood and cells?
Via interstitial fluid
What do humans need to survive?
Nutrients
Oxygen
Water
Normal body temp
Appropriate atmospheric pressure
Why do we need nutrients to survive?
Carbs- main source of energy
Proteins- cell building and cell chemistry
Fats- long term energy storage
Minerals and vitamins- involved in chemical reactions as well as structural purposes
Why do we need oxygen to survive?
Essential for release of energy from foods
Why do we need water to survive?
Most abundant chemical in body
Provides watery environment needed for chemical reactions
Why do we need consistent temp in body?
If below or above 37 degrees rates of reactions are affected
Why do we need an appropriate pressure to survive?
For adequate breathing and gas exchange in lungs
Homeostasis
Maintenance of relatively stable internal conditions despite continuous changes in environment
Dynamic state of equilibrium, always readjusting as needed
Variables
Factors that can change
Blood sugar, body temp, blood volume
Control of variables involves receptor, control center, effector
Homeostatic controls
Body must constantly be monitored and regulated to maintain homeostasis - nervous and endocrine system play a role
Receptor
Monitors the environment
Responds to stimuli- things that causes changes in controlled variables
Control center
Determines seat point at which variable is maintained
Receives input from receptor
Determines appropriate response
Effector
Receives output from control center
Provides the means to respond
Response either reduces stimulus (negative feedback) or enhances stimulus (positive feedback)
Negative feedback
Response reduces or shuts off original stimulus
Variable changes in opposite direction of initial change
E.g regulation of body temp, regulation of blood glucose by insulin
What happens when homeostasis level disrupted?
Stimulus produces change in variable
Receptors detect change
Info sent along afferent pathway to control center
Info sent alone efferent pathway to effector
Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level
Positive feedback
Response enhances the original stimulus
Amplifying effect as feedback causes variable to continue in same direction as initial change
Usually controls infrequent events that do not require continuous adjustment E.g enhancement of labour contractions by oxytocin
Homeostasis imbalance
Increase risk of disease
Contributes to changes associated with aging
Control systems become less efficient
If negative feedback mechanisms become overwhelmed, destructive positive feedback mechanisms may take over E.g heart failure
