Lecture 2 Flashcards
Definition: physiology
The study of functions within an organism.
Definition: anatomy
The study of structures.
Only known cells in the body to have flagella.
Sperm cells.
Levels of organization.
Molecules - organelles - cells - tissues - organs - systems - organism.
Definition: differentiate.
Specialize.
Types of tissue in organs.
Epithelium, nervous tissue, and muscle tissue.
Blood is…
A transport medium.
Definition: homeostasis.
Keeping the internal environment stable while the external environment fluctuates.
The immune system in the blood is part of which system?
The distribution system.
Definition: histology.
The study of tissues.
Definition: gross anatomy.
The study of the body and its parts using only the naked eye.
Definition: microanatomy.
The study of tissues and cells.
How does the heart beat?
Electrical signals stimulate myocytes (muscle cells) to contract. Intercalated discs within the heart help propagate the electrical signals.
What causes channels to open and close within the heart?
Ion gradient fluctuation.
Which systems connect to the whole body?
Cardiovascular and respiratory systems.
Which systems control everything?
The endocrine and nervous system.
What does the endocrine system govern?
Long-acting and long-term processes (examples: puberty, pregnancy, lactation).
Function of the digestive system.
The digestive system breaks down food into nutrients, which then enter the blood.
Definition: cells.
The smallest living units.
Characteristics of mammalian cells.
They are surrounded by a cytoplasm within a membrane, and they have a nucleus.
Role of mitochondria.
Energy production.
Role of Golgi.
Packaging and post-translational modification.
Mitosis.
Division of DNA and its packaging materials (histones). When the cell prepares to divide, chromatin condenses into chromosomes; this causes all transcriptional activity to stop.
Which type of cells can undergo mitosis?
All cells that can regenerate.
Which cells cannot undergo mitosis?
Neurons: these are one of the most highly specialized types of cells. Cardiac cells: they have poor regeneration capacity.
Definition: specialization of a cell.
Control of gene expression and unique transcriptomes and proteosomes.
Induction of stem cells leads to…
Differentiated cells.
What distinguishes cell types from one another?
Function: gene expression is different for each type of cell.
How do cell types differentiate?
Variations in gene expression caused by influences from the environment; specific conditions and growth factors,
Factors essential for cell differentiation:
Cell-cell communication, growth factors, ECM (extracellular matrix), and cell location.
Definition: gastrulation.
A phase in early embryonic development.
Gastrulation gives rise to which 3 cell types?
Endoderm, mesoderm, and ectoderm.
After fertilization, how do zygotes differentiate?
By mitosis.
Germ layers give rise to…
Rudimentary embryo structures.
Cells and tissue types that arise from the ectoderm:
Integument (skin), lens of the eye, and nervous system.
Cells and tissue types arising from the mesoderm:
Circulatory system, excretory system, muscles, connective tissue, and organs.
Cells and tissue types arising from the endoderm:
lining of the digestive tract, parts of the liver, pancreas, thyroid, and bladder.
The 4 major tissue types:
Epithelial tissue, connective tissue, muscle tissue, and nervous tissue.
Definition: tissue level.
An organization of similar cells specialized to perform a certain function.
Epithelial tissue.
Found on anything open to the exterior (such as GI tract); avascular (does not have a blood supply), so it relies on underlying connective tissue for nutrients.
Connective tissue.
Dermis.
Muscle tissue.
Contractile tissue.
Nervous tissue.
Highly specialized and excitable, can generate action potentials and nerve impulses.
The epithelium lies over which type of tissue?
Connective tissue composed of fibroblasts and stroll cells.
Columnar secretory epithelium:
The cells are column shaped.
Kidneys are composed of which type of epithelial cells?
Cuboidal epithelium: made of nephrons, the uterine forming structures of the kidney.
Are there blood vessels in epithelium tissue?
No, it is avascular.
Characteristics of the epithelium:
Contains one or more dense layers of cells; contains little ECM.
Functions of the ECM:
Covers and protects the body surface, lines body cavities, and helps the movement of substances (glandular activity, i.e. secretion).
Where can epithelial tissue be found?
Lining of the respiratory tract, urinary tract, and in glands of the body; also in the digestive tract.
Characteristics of connective tissue:
Few cells surrounded by a lot of ECM (extracellular matrix).
Functions of connective tissue:
To connect, anchor, and support body structures, as well as enable transport.
Where can connective tissues be found?
Bones, tendons, blood, and fat.
ECM (extracellular matrix) is made up of…
Fibres in a protein and polysaccharide matrix.
Variations in ECM composition determines…
The properties of the connective tissue.
Specialized forms of ECM:
Tendons and cartilage.
Classification of general connective tissue:
Loose or dense, depending on fibre arrangement.
Name some connective tissues.
Bone, blood, and lymph.
The ECM is made of…
Fibres and protein polysaccharides; fibroblasts are the cell types that secrete the cellular matrix.
Which cell type secreted the cellular matrix?
Fibroblasts.
Calcified ECM will give rise to…
Bones or teeth.
All connective tissues (fibroblasts) secrete ECM except…
Blood cells.
Characteristics of muscle tissue.
Long, fibre-like.
Functions of muscle tissue:
To contract and generate force.
Muscle tissue can be found in…
The heart, skeletal muscle, and hollow organs like the bladder or the uterus.
Name the 3 types of muscle tissue:
Skeletal muscle, cardiac muscle, and smooth muscle.
Which type of muscle tissue acts under voluntary control?
Skeletal muscle.
Examples of smooth muscle contractions:
The esophagus: food goes down by peristaltic contraction.
Characteristics of nervous tissue:
Cells specialized for conducting nerve impulses.
Functions of nervous tissue:
To initiate and transmit electrical impulses.
Nervous tissue can be found in…
Concentrated in he brain and spinal cord, but present everywhere in the body.
Definition: organ level.
Combination of different tissue types that perform a special function.
Name different tissue types found in the stomach.
Smooth muscle (aids in gastric emptying and peristalsis), nervous tissue, loose connective tissue, epithelium, and connective tissue (blood vessels).
Goal of homeostasis.
To return to the set point.
Consequence of homeostatic failure:
Disease or death; the body does not function optimally.
Urine is an example of homeostasis; why?
Concentration of urine varies according to blood concentration.
Definition: set point.
An acceptable or normal range.
Some examples of homeostasis:
Temperature regulation, carbon dioxide regulation, and blood glucose level regulation.
Preferred energy source of living cells:
Glucose.
Homeostasis in a low glucose environment:
The body slows glucose uptake so the concentration of glucose in the blood remains constant; more glucose is then released by the liver.
Definition: hypoglycaemia.
Cells are deprived of glucose.
Effects of hypoglycaemia:
Glucagon secretion is stimulated in the liver, which is an antagonistic agent to insulin.
The mechanism for the self-regulation of homeostasis.
Feedback control loops.
Basic components of a homeostatic mechanism:
Sensor, integrating or control centre, effector mechanism,. and feedback.
The effector mechanism in homeostasis…
Brings about the changes required for the system to return to its set point.
Negative feedback control mechanisms.
Inhibitory, they reset physiological variables, the regulate homeostasis, and they are more common than positive feedback control mechanisms.
Positive feedback control mechanisms.
Less common than negative feedback control mechanisms, they are stimulatory, they amplify or reinforce the change that is occurring, they produce destabilizing effects that disrupt homeostasis, and they bring specific body functions to swift completion.
Example of positive feedback control mechanism:
Child birth: the uterus contracts due to the release of oxytocin, which pushes down on the cervix, which causes even more release of oxytocin; this is an example of signal amplification.
