Definitions Book 3 Flashcards
Sensory receptor
A specialised structure that can detect a specific stimus and convert stimulus energy to a changing membrane potential to be transmitted to CNS as action potentials for sensory perception and interpretation
Sensory amplification
During conversion of stimulus energy to action potentials, sensory signals can by strengths by sensory amplification
Sensory adaptation
If the stimulation is continuous, many receptors show a decrease in responsiveness
Chemoreceptor
Sensory receptors which respond to chemical stimuli
Thermoreceptors
Specialised temperature sensitive receptors which detect the heat and cold on the body surface and in internal environment of body
Photoreceptor
Sensitive to light
Mechanoreceptors
Respond to stimuli arising from mechanical energy deformation such as pressure, touch, stretch, sound and motion
Pain receptors
Detect stimuli that reflect harmful conditions that could arise from extreme pressure, temperature and certain chemicals that could damage tissues
Endocrine glands
Ductless glands consisting of specialised cells which secrete hormones (chemical messengers) that diffuse directly into the bloodstream and reach specific target organs/tissues
Hormone
Specific type of signalling molecule secreted by an endocrine gland/cells which travel the bloodstream and act on specific target cells elsewhere in the body, changing the target cells functioning
Target cells
Only cells which have matching receptors for that hormone, and are receptive to chemical signal although the hormone reaches all body cells
Trophic hormones
Some hormones secreted by anterior pituitary redirect chemical signals from hypothalamus to other endocrine glands. These are trophic hormones
Monocular vision
Seeing the visual field with only one eye
Binocular vision
Seeing the visual field with two eyes with greater overlapping fields of view
Homeostasis
A steady state condition where the body’s intern environment remains relatively constant within narrow physiological limits despite significant changes in the external environment
Internal environment
Immediate surroundings of body cells which provides the cells the medium in which they have to live
Response
A physiological activity that helps return the variable towards the set point level
Zygote
The 2 haploid pronuclei of the mature ovum and sperm fuse to produce a diploid, single cell known as a zygote
Fertilisation
Fusion of haploid pronuclei of sperms and ovum
Cleavage
Series of mitotic divisions that occur 24 hrs after fertilisation
Implantation
7 days after fertilisation, the blastocyst attaches to endometrium of mothers uterus
Placenta
Embryonic trophoblast and the mother’s endometrium intermingles to form placenta
Umbilical cord
Flexible cord like structure containing blood vessels and attaches embyro/fetus to the placenta during gestation
Pregnancy/gestation
Condition of carrying one or more developing offspring inside a female’s uterus
Labour
A series of strong rhythmic uterine contractions that push the fetus and placenta out the body
Lactation
Secretion and ejection of mothers milk from mammary glands
Contraception
Deliberately preventing pregnancy
Abortion
Premature termination of a pregnancy in progress
Infertility
Inability to conceive offspring
Hydrostatic Skelton
A fluid filled cavity enclosed within body wall
Exoskeleton
Rigid outer covering of the body of animal which acts as the skeleton
Endoskeleton
Hard skeleton buried in soft tissues of the animal
Fontanelles
Soft membranous regions of the cranium which allow slight compressions at birth, facilitating parturition
Sutures
Immovable joints present between skull bones to provide more protection
Sinuses
Several air filled cavities lined by ciliated mucous membranes present in skull
