1: Levels of Organisation Flashcards
functions of living things
responsiveness
growth
reproduction
movement
metabolism
level of organisation
chemical level
cells
tissues
organs
organ systems
organisms
chemical level
atoms (hydrogen, carbon, oxygen etc.)
molecules (water, sugars, fatty acids etc.)
cells
cell is composed of many organelles
they are the smallest unit of life
they become specialised for different functions (differentiated) e.g. neuron, smooth muscle, fat cell
tissue
tissues are similar cells that combine to form a special function
epithelia = around outside, covers exposed surfaces, lines tissues passageways and chambers, produces glandular secretions
connective = fills internal spaces, provides structure and support
muscle = contracts to produce active movement
neural = conducts electrical impulses, transfers information around body
organs
a discrete collection of two or more tissues cooperatively performing a function
organ systems
interaction of organs
organism
all organ systems work together to maintain life and health
highest level of organisation
integumentary system
consists of: skin, hair nails
function: protection against environmental hazards, thermoregulation, sensory information
skeletal system
consists of: bones, joints
function: support, protects tissues, store minerals, forms blood cells
muscular system
consists of: muscles, tendons
function: movement, protection, support for tissues, produces heat
nervous system
consists of: peripheral nervous system (peripheral nerves) and central nervous system (brain, spinal cord)
function: control body’s processes through electrical impulses, directs immediate responses, provides and interprets sensory information
endocrine system
consists of: glands, pancreas, ovary, testes
function: directs long-term changes in activities of organ systems
cardiovascular system
consists of: heart, blood vessels, blood
function: transport cells and dissolved material (oxygen, nutrients, waste, CO2)
lymphatic system
consists of: lymphatic vessel, thymus, spleen, lymph nodes
function: defends against infection and disease, returns tissue fluids to the bloodstream
respiratory system
consists of: lungs, passageways
function: delivers air to lungs for gas exchange, produces sound of communication
digestive system
consists of: muscular tubes from mouth to anus with many organs throughout
function: ingest and breakdown food into nutrients to absorb
urinary system
consists of: bladder, urethra, kidney, ureter
function: excretes waste products, controls water balance by regulating amount of urine produced
reproductive system
consists of: male and female reproductive organs
function: reproduce, produce sperm and hormones, produce eggs and hormones, support foetus
anatomical postition
facing forward
feet together
hands by side
palms facing forward
terminology
superior = towards head
inferior = towards feet
proximal = closest to torso
distal = further from trunk
lateral = to side of body
medial = towards midline of body
terminology pt. 2
posterior (dorsal) = back
anterior (ventral) = front
cranial = towards head
caudal = towards feet
superficial = close to surface
frontal plane = separates front from back
sagittal plane = splits LHS from RHS
transverse plane = horizontal slice through the body
cavities
cavity = closed, fluid filled spaces lined by a thin tissue layer called a serous membrane, vital organs suspended in the cavities
thoracic cavity = two pleural cavities (each surrounding a lung), a pericardial cavity (surrounds heart)
ventral cavity = thoracic, abdominal and pelvic organs
dorsal cavity = brain and spinal cord
homeostasis
homeostasis = maintenance of a constant internal environment
regulation = adjustment in physiological systems that preserves homeostasis
receptors sensitive to change
control centres receive and process information
effectors respond to commands
negative feedback
= a variation outside normal levels that triggers an automatic response
negative feedback maintains normal range not a fixed value
positive feedback
= an initial stimulus produces a response that reinforces that stimulus
e.g. blood clotting
damage to blood vessel releases chemicals to start clotting
chemicals start chain reactions to accelerate process
