DHUBS1 - week 2 Flashcards
(24 cards)
what is embrylogy
the study of embroys and their development
steps of fertilisation
- Sperm penetrates between granulosa cells
- Some of the zona pellucida is degraded by acrosomal enzymes
- Sperm and egg plasma membrane fuses
- The sperm nucleus disassociates and enters cytoplasm
- Additional sperm can no longer penetrate the zona pellucida
- Cortical granulised release enzymes that harden zona pellucida and strip it of sperm receptors. Hyalin attracts water by osmosis
- Sperm and egg pronuclei in a nuclear envelope
cleavage and blastula stage
- Cleavage: embryo stays the same size (more cells, smaller size with each division)
- Cleavage ends with the formation of a blastocyst in mammals (outer layer of cells = trophoblast = responsible for implantation, inner cell mass = becomes the organism)
what is gastrulation
-Gastrulation is the process of cellular rearrangement involving migration, invagination and differentiation of cells (occurs in week 3)
what are the three primary germ layers
Endoderm: within skin
Mesoderm: middle skin
Ectoderm: outside skin
what is human development
the process of systematic, gene directed changes through which an organism forms the successive stages of its life cycle
what ar the 4 substage of the process of development
cell division
differentiation
pattern fomration
morphogenesis
what is cell division
- necessary in order to allow a single cell to develop into a multicellular organism
- very first process that must occur during embryogenesis
what is differentiation
- orchestrated changes in gene expression between cells are required to create the specialised cell lineages
- cells become “determines” befroe differentiated
what is pattern formation?
cells must become orientated to the body plan/species it will become
what is morphogenesis
- as development proceeds in the organs and anatomical features form by the way of cell division, cell death, migration, changes in shape and differentiation
- the generation of ordered fomr and structure
what are tissues?
a group of similar cells organised to perform a specific function
what are the four primary tissue types?
epithelial tissues
connective tissues
muscle tissue
nervous tissue
what is hoeostasis?
the maintenance of relatively stable internal body conditions despite change that occur inside or outside the body
homeostasis regulation: what are the two general mechanisms?
auto-regulation: adjustment in response to a local environmental change
extrinsic regulation: adjustment in response to more wide spread environmental change. results from activities of the nervous or endocrine system.
Homeostasis regulatory mechanism consist of 3 components, what are they?
Receptor: sensor that is sensitive to a particular stimulus or environmental change
Control centre: receives and processes the information supplied by the receptor and sends out commands
Effector: cell or organ that responds to the commands of the control centre activity either opposes or enhances the stimulus
what is negative feedback?
Maintains homeostasis by returning a variable to the tolerance range by reducing the original stimulus. this is most used by control systems that use hormones (e.g. controlling body temperature)
what is positive feedback?
enhances the original stimulus (childbirth)(if you have a cut its a positive feedback loop)
What are the major organs of the integumentary system?
skin
hair
nails
sweat glands
what is the function of the integumentary system?
Protection against environmental hazards
Excretion pf salt, water and organic waste
Maintenance of body temperature
Synthesis of vitamin D
what is the skin made up of?
epidermis and dermis
explain epidermis
consists of stratified squamous epithelium which contains two types of cells:
- keratinocytes: epithelial cells that contain a protein called keratin
- melanocytes: produce melatonin
explain dermis
Contains capillaries, lymphatic vessels, and sensory neurons that supply skin surface
