Lab Safety/Orientation
...
Homeostasis
the condition of balance in the body's internal environment due to the constant interaction of the body's many regulatory processes
Cell Cycle summary
G1 --> S Phase --> G2 Phase --> Mitosis --> cytokinesis
Mitosis
Nuclear division/ distribution of 2 sets of chromosomes into separate nuclei
Cytoplasmic Division
division of a cell's cytoplasm and organelles into two identical cells/ usually begins in late anaphase with the formation of the 'cleavage furrow' (slight indentation in the plasma membrane) & is completed after telophase
What happens when cytokinesis is complete?
interphase begins
Interphase
period between cell divisions/ the cell replicates its DNA/ the cells does most of its growing in this phase/ Consists of 3 phases: G1, S, & G2
G1 phase of Interphase
ast 8-10 hours/ the cell is metabolically active/ it replicates most of its organelles, centrosomes, cytosolic components, but NOT its DNA
S phase of Interphase
last 8 hours/ replication of DNA and centrosomes
G2 phase of Interphase
lasts 4-6 hours/ cell growth continues/ enzyme and protein synthesis continue/ replication of centrosomes complete
Mitotic Phase of the cell cycle
results in the formation of 2 identical cells/ consists of nuclear division (mitosis) and cytoplasmic division (cytokinesis)
Early Prophase
the chromatin fibers condense and shorten into chromosomes (each with individual strands called chromatids)/
Centromere
A constricted region that holds the chromatid pair together
Late Prophase
tubulins in the pericentriolar material of the centrosomes start to from the MITOTIC SPINDLE/ as the microtubules lengthen, they push the centrosomes to the poles (ends) of the cell so that the spindle extends from pole to pole/ the nucleus disappears and
Mitotic Spindle
a football-shaped assembly of microtubules that attach to the outside of the centromeres
Metaphase
the microtubules of the mitotic spindle align the centromeres of the chromatid pairs at the exact venter of the mitotic spindle (called the metaphase plate)
Anaphase
the centromeres split, separating the 2 members of each chromatic pair, which move toward opposite poles of the cell/ once separated, the chromatids are termed 'chromosomes'/ the chromosomes are pulled by the microtubules of the mitotic spindle (appears V
Telophase
the final stage of mitosis/ begins after chromosomal movement stops/ the identical sets of chromosomes (now at opposite ends of the cell) uncoil and revert to the threadlike chromatin form/ a nuclear envelope forms around each chromatin mass/ nucleoli rea
Meiosis
the process that produces haploid (n) gametes/ consists of 2 successive nuclear divisions: Meiosis I and Meiosis II
Meiosis I
homologous chromosomes undergo synapsis (pairing) and crossing-over/ the net result is 2 haploid cells that are genetically unlike each other and unlike the starting diploid parent cell that produced them/ consists of Prophase I, Metaphase I, Anaphase I,
Prophase I
chromosome shorten & thicken/ mitotic spindle forms
What occurs in Prophase 1 in Meiosis & not in Prophase in Mitosis?
1) the 2 sister chromatids of each pair of homologous chromosomes pair off (called "synapsis")/ the resulting 4 chromatids from a structure called a "tetrad"
2) parts of the chromatids of 2 homologous chromosomes may be exchanged with one another, called
What does Crossing-over result in?
the resulting cells are genetically unlike each other and genetically unlike the starting cell that produced them/ results in "Genetic Recombination", the formation of new combinations of genes (results in the variation among humans)
Metaphase I
tetrads formed by the homologous pairs of chromosomes line up along the metaphase plate of the cell (homologous chromosomes side by side)
Anaphase I
members of each homologous pair of chromosomes separate as the are pulled to opposite poles of the cell by the microtubules attached to the centromeres/ the paired chromatids (held by a centromere) remain together
How are Anaphase I in Meiosis & Mitotic Anaphase different?
In Anaphase I, the centromere remains intact. In mitotic anaphase, the centromeres split and the sister chromatids separate
Telophase I/ Cytokinesis
Similar to Mitosis
Meiosis II
2 haploid cells divide to form 4 haploid cells/ consists of: Prophase II, Metaphase II, Anaphase II, and Telophase II/ these phase are similar to Mitosis; the centromeres split, and the sister chromatids separate and move toward opposite poles of the cell
Heredity
the transfer of genetic traits (like hair or eye color) from parents to offsprings, generation after generation
Punnett Squares
in constructing a Punnett Square, the possible paternal alleles in sperm are written on the left side & the possible maternal alleles in ova (or secondary oocytes) are written at the top
Homozygous
a person with the same alleles on homologous chromosomes. PP is homozygous dominant & pp is homozygous recessive
Heterozygous
an individuals with different alleles on homologous chromosomes. EX- Pp
Monohybrid Crosses
the inheritance of only one trait is studied using a single pair of alleles
Incomplete Dominance
blending of traits/ neither allele for a gene is dominant over the other and the offspring show an intermediate phenotype (ex-curly hair & straight hair= wavy hair)
Codominance
no blending characteristics/ both genes are expressed equally in the heterozygote
Sex-linked Characteristics
Sex-linked traits are genetic characteristics determined by genes , which are located on sex chromosomes/ there are 22 pairs of autosomes and 2 sex chromosomes for each person
Sex
...
Population Genetics
...
Endocrine System
acts with the nervous to coordinate functions of all body systems/ controls body activities by releasing mediators (hormones)
What is a hormone?
a mediator molecule that is released in one part of the body, but regulates the activity of cells in other parts of the body/ most enter interstitial fluid and then the bloodstream
Endocrine Glands
secrete their hormones into the interstitial fluid surrounding secretory cells, rather than ducts. From the interstitial fluid, hormones diffuse into blood capillaries & blood carries them to target cells throughout the body
Hormone Functions
Synthesis of molecules within the cell (ex-estrogen)/ changing plasma membrane permeability (ex-aldosterone)/ altering cellular metabolism (ex-thyroxin)/ secretion of cell products (ex-thyroid-stimulating hormone)/ contraction of smooth muscle (ex-oxytoci
Hypothalamus
couples the nervous & endocrine systems together/ "master gland"/ the hypothalamic hormones & several anterior pituitary hormones are called "tropic hormones" because they target another endocrine gland
Pituitary Gland
also called the 'hypophysis'/ the infundibulum is the stalk that connects the hypothalamus to the pituitary gland and contains a direct blood supply to the pituitary/ separated into anterior & posterior
Anterior Pituitary
AKA 'adenohypophysis'/ composed of glandular epithelial tissue that makes and secretes 7 hormones: hGH, TSH, FSH, LH, PRL, ACTH, MSH
Posterior Pituitary
AKA 'neurohypophysis'/ composed of nervous tissue that stores and releases into the blood two hormones that are not synthesized in the posterior pituitary: ADH, OT/ these hormones are synthesized within cell bodies of hypothalamic neurons, packaged into v
Thyroid
has 2 lobes with a connecting isthmus and lies on both sides of the trachea near the thyroid cartilage (Adam's apple) of the larynx/ has large follicles that are filled with a protein called "colloid"/ simple cuboidal or simple columnar cells called "foll
What do Follicle Cells synthesize?
thyroglobulin, a thyroid hormone precursor store in colloid. Thyroglobulin produces 2 thyroid hormones (TH), T4, and T3
Parathyroid Glands
embedded in the posterior surface of the thyroid gland are four small, round Parathyroid Glands. Two types of epithelial cells are found in the parathyroid glands: principal cells (produce PTH) & the oxyphil cells
Adrenal Glands
AKA "suprarenal glands" because of their location on the superior part of the kidneys/ each adrenal gland is surrounded by a 'capsule' and is composed of an outer cortex & central medulla
Adrenal Cortex
is glandular and can be divided histologically into 3 layers:
1) Zona Glomerulosa- the outermost layer whose cells are arranged in little columns (secretes the hormone- mineralcorticoids, with 'Aldosterone' being the main hormone secreted)
2) Zona Fascicu
What are Androgens?
hormones that increase male characteristics
Adrenal Medulla
made up of nervous tissue that is stimulated by the sympathetic nervous system to secrete 2 hormones: epinephrin & norepinephrin (NE)
Pancreas
has endocrine & exocrine functions/ endocrine cells, called "pancreatic islets", are located as little islands among the clusters of acini cells/ the alpha cells (A cells) in the pancreatic islets secrete 'Glucagon' and the beta cells (B cells) secrete 'I
Ovaries
are female gonads that not only produce & house the ova as they mature, but are also endocrine organs that produce 2 major hormones: Estrogen & Progesterone
Testes
are male gonads that not only produce sperm, but also produce and secrete Androgens, primarily Testosterone
Pineal Gland
or Pineal Body, is a small, cone-shaped gland that is located in the brain posterior to the thalamus & superior to the cerebellum/ it secretes 'Melatonin' in darkness and, to a lesser degree in the daytime/ helps set the body's biological clock
Thymus
plays a role in immune functions and is located anterior & superior to the heart/ much larger in children and regresses in size as person ages/ produces the hormone 'Thymosin'
Reproductive System
...
Male Reproduction
...
Male- Structures
...
Duct System
...
Accessory Sex Glands
...
Semen
...
Penis
...
Histology of the Testes
...
Female Reproduction
...
Uterus
...
Vagina
...
External Genitalia
...
Mammary Glands
...
Oogenesis
...
Meiosis 1
...
Meiosis 2
...
Histology of the Ovary
...
Menstrual Cycle
...
Female Hormones
...
Uterine Endometrial Cycle
...
Follicular Development
...
Writing a Lab Report
...
Dissection
...