Anatomy workbooks Flashcards
What is the duration of pre-embryonic period?
First two weeks of prenatal development is referred to as pre-embryonic period
How do you define fetal period?
The time of prenatal development from week 9-till birth is referred to as fetal period
Define zygote
A fertilised ovum (oocyte, egg) is referred to as zygote
Define zona pellucida; what is its function?
Zona pellucida (means transparent zone) is a specialised extracellular matrix that surrounds the developing oocyte (egg, ovum). It is made up of glycoproteins; provides nutritional and mechanical support; helps in binding of sperm; promotes acrosomal reaction; prevents polyspermy
What are the outcomes of fertilisation?
- Restores the normal diploid number of chromosomes (46).
- Secondary oocyte completes meiosis.
- The sex of the embryo is established
- Initiation of cell division (cleavage)
Define the word ‘Cleavage’ in what is the outcome of ‘cleavage’?
Cleavage is the rapid mitotic division of cells in a zygote.
Zygote undergoes rapid cell divisions (cleavage) with no overall growth, producing a cluster of cells.
Different cells derived as a result of cleavage are called blastomeres resulting in a compact mass/ball of cells called morula.
What is the significance of ‘embryonic period’?
During the embryonic period most of the organ systems are established. This is the period from week 2 to week 8.
What are the normal sites of implantation of embryo?
Normal site for implantation is the upper (fundus), or posterior wall of the uterus (also may establish on side walls)
What is the outcome of implantation of embryo in fallopian (uterine) tubes?
Ectopic / tubal pregnancy, which usually results in rupture of the tube (a medical
emergency)
What are the names of the three major germ layers in an embryo?
Ectoderm, mesoderm, endoderm
What is the structural unit of:
Epithelium_________
Connective tissue___________
Muscle tissue__________
Nervous tissue_________
Epithelium_____cell_____
Connective tissue___cells, fibres, matrix_________
Muscle tissue_____muscle cell_______
Nervous tissue____neuron________
How do you define the term ‘Tissues’’? Name the four basic/main tissues of the human body.
Tissue is a group of cells that have similar structure and that function together as a unit.
Epithelium, Connective tissue, Muscle tissue, Nervous tissue-
What is the key function of each basic tissue type? (4)
Epithelium-protective linings, secretion, absorption
Connective tissue-connects/anchors, support, locomotion, repair
Muscle tissue-movement
Nervous tissue-generates, conducts nerve impulses
State the embryonic origin of each basic tissue type
Epithelium-outer linings/skin =ectoderm; inner linings endoderm Connective tissue-mesoderm Muscle tissue-mesoderm Nervous tissue-ectoderm
Define the word ‘endothelium’
‘ENDOTHELIUM’ is the inner epithelial lining of blood vessels (and lymphatic vessels)
What are the functions of the adipose tissue in the human body?
Insulation, protection (creates padding around organs e.g. eyeball)
What is the function of ‘cartilage’ in our body?
Flexible support to skeleton, framework
Why is bone tissue referred to as ‘Modified Connective Tissue’
Bone tissue referred to as ‘Modified connective tissue’ because its matrix is modified due to mineralisation i.e. mineralised
Which main body system is derived from ‘ectoderm’ germ layer?
Nervous system
Name any two surface modifications of epithelium (epithelial cells)
Cilia, microvilli
Define the term ‘gland’
A gland is a cell or group of cells modified to secrete chemical substances that are either released into its surroundings (exocrine gland) or into blood stream (endocrine gland)
Name at least three primary functions of the SKIN.
Protection, heat/thermo regulation, sensation (secretion, absorption, vit-D metabolism).
Name the two histological layers of skin?
Dermis and epidermis (also then sub-cutis)
How do the two layers of the skin differ?
Epidermis, is made of closely packed epithelial cells (stratified squamous epithelium), and
Dermis, made of dense, irregular connective tissue that houses blood vessels, hair follicles, sweat glands, etc.
What is an arrector pili and what is its function?
This is tiny muscle that anchors to bases of hair follicles and also anchored to dermal tissue at their other end.
Function: In order to generate heat or when body is cold, or in fear situations-arrector pili muscles contract all at once, causing the hair to “stand up straight” on skin (goose bumps)
Embryologically, which germ layer gives rise to skin?
Ectoderm (ecto-means outside)
What is the function of sebaceous glands and sebum?
Sebum is produced by sebaceous glands (holocrine-when whole gland disintegrates). The gland cells last about a week, (from formation to discharge). These sebaceous glands produce a lipid-based substance-SEBUM which is broken down by bacterial enzymes (lipases) in sebaceous duct
The oil on surface of skin is a mixture of sebum, lipids (from the surface skin cells), sweat and environmental particles
Can the different types of nerve endings/receptors in the skin be related to various types of sensations (e.g. pain, touch, temperature, pressure)?
Yes, skin has nerve endings and sensory receptors (in epidermis and dermis) for various sensations
What are the key functions of muscle tissue?
Muscle tissue/ Muscle functions include maintenance of posture, locomotion, and circulation, digestion
What are the three histological varieties of muscles?
Three distinct muscle types are: skeletal, cardiac and smooth
Which types of muscles are under involuntary control?
Cardiac and smooth
Why is skeletal muscle and cardiac muscle also referred to as striated muscle’?
Striated means stipes: the striped appearance of muscles is due to discrete arrangement of contractile protein; arranged in myofibrils as discrete well-aligned units, this gives appearance of light and dark bands under microscope (hence striated)
Both cardiac and skeletal muscle have striated appearance under the microscope.
How may they then be differentiated? (between cardiac and skeletal muscle)
Cardiac muscle can be differentiated from skeletal muscle by the presence of intercalated discs which accelerate APs
What is the structural and functional unit of a skeletal muscle at histological (microscopic) level called?
A sarcomere
How are the functional pairs of skeletal muscle named?
Prime movers (agonist) Antagonist (muscles acting from opposite side of joints) [although they do not really oppose each other’s actions rather facilitate each other’s actions) Synergists/ supporting muscles OR Flexors-extensors Abductors-adductors Medial rotators-lateral rotators
What is the role of connective tissue coverings of muscles (Skeletal muscle)?
Epimysium, perimysium and endomysium are the connective coverings; their role is to form protective coverings and also enhance the efficacy of muscle contraction
Name three regions where smooth muscle is found.
Arteries, uterus, bladder (walls of other internal organs)
What is the endoplasmic reticulum of the muscle referred to as?
Sarcoplasmic reticulum (sarco-means flesh)
What result would be expected from premature closure of epiphysial plates?
Short height
Where is red marrow found in an adult?
In flat bones; sternum, ribs, skull, hip bones,
Which portion of the body is examined most frequently in the assessment of skeletal maturation?
Hand, wrist radiographs
Are epiphysial centers visible on a radiograph (X-Ray) in the knee at birth?
Yes
Which parts of the limb bones are cartilaginous (or have cartilage covering) in the adult?
Ends of long bones and joint surfaces
Is there a cartilage present in the adult skeleton?
Yes, at ends of long bones (joint surfaces), and ends of ribs
What is membrane bone?
A bone that develops in membranous tissue or within membranous tissue (ribs) (intramembranous ossification is the formation method)
Provide examples of (a) plane, (b) hinge, and (c) ball-and-socket joints.
a) wrist
b) elbow, knee
c) shoulder, hip
What is (a) the origin and (b) the functions of synovial fluid?
(a) Synovial membrane of joints
(b) Lubricates joint surfaces, facilitates friction-free movements
What is the total number of bones in the adult human body?
206 (more in younger children due to non-fusion)