Nursing Science 2 exam 2 2025

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Inheritance

The passage of hereditary traits from one generation to another.

Genetics

The branch of biology that deals with inheritance.

Genotype

The genetic makeup of an individual, represented by alleles (e.g., Pp).

Phenotype

The physical characteristics determined by the genotype and the environment (e.g., brown hair, blue eyes).

Mutation

A permanent, heritable change in a gene that causes it to have a different effect than it had previously.

Homozygous

An individual with the same alleles on homologous chromosomes (e.g., PP or pp).

Heterozygous

An individual with different alleles on homologous chromosomes (e.g., Pp).

Dominant allele

An allele that is always expressed, overriding the corresponding allele on the other homologous chromosome.

Recessive allele

An allele that is completely hidden or masked by the presence of a dominant allele and is expressed only when no dominant allele is present.

Punnett square

A method of showing the possible genetic combinations in offspring of two individuals.

Autosomes

Any chromosomes other than sex chromosomes; humans have 22 pairs of autosomes.

Sex chromosomes

The 23rd pair of chromosomes that determine an individual's sex; XX for females and XY for males.

Sex-linked traits

Traits determined by genes located on the sex chromosomes, often observed as X-linked traits.

Polygenic or Complex inheritance

Inheritance controlled by two or more genes, often influenced by environmental factors.

Teratogen

Any agent or influence that causes developmental defects in the embryo.

Cystic fibrosis

An autosomal recessive disease characterized by altered function of exocrine glands, particularly affecting the lungs and pancreas.

Down syndrome

A genetic disorder caused by trisomy of chromosome 21.

Environmental influences

Factors that affect phenotype, including nutrition, exposure to chemicals, and other environmental conditions.

Autosomal dominant genetic disorder

Conditions that manifest when at least one allele is dominant and can lead to disease without needing two copies.

X-linked traits

Genetic characteristics determined by genes located on the X chromosome, often affecting males more severely as they have no backup copy on the other x chromosome like females have.

Multiple allele inheritance

A form of inheritance where more than two alleles exist for a gene, leading to a variety of possible phenotypes among individuals. An example is blood groups.

Sex determination

Depending on whether the secondary oocyte is fertilised by a sperm containing a Y or X chromosome because all oocytes have an X. Sex is therefore determined by the father (sperm).

Ovaries

Glands in the female reproductive system that produce oestrogen, progesterone, and the secondary oocyte. Positioned laterally to the uterus by several ligaments.

The ovarian cortex contains follicles/oocytes, the ovarian medulla consists of connective tissue and blood/lymphatic vessels.

Uterine tubes (Fallopian tubes)

Tubes that transport the ovum from the ovaries to the uterus, where fertilization generally occurs. They have fimbrae and cilia that sweep the oocyte up from the abdominopelvic cavity inside. it has two sections - the ampulla where fertilisation occurs and the isthmus.

Menstrual cycle

The regular natural change that occurs in the female reproductive system, involving the preparation of the endometrium to receive and nourish a fertilized ovum.

Corpus luteum

A temporary endocrine structure formed from the follicle after ovulation, which secretes progesterone and some oestrogen.

Endometrium

The innermost functional layer of the uterus that is shed during menstruation and regenerates in preparation for a potential pregnancy.

Cervical mucus

Mucus produced by the cervical glands that changes in consistency throughout the menstrual cycle, aiding or impeding sperm passage.

Prolactin

A hormone involved in initiating and maintaining milk production in the mammary glands.

Ectopic pregnancy

A pregnancy that occurs outside the uterus, commonly in the fallopian tubes, often due to blocked tubes.

GnRH (Gonadotropin-releasing hormone)

A hormone secreted by the hypothalamus that stimulates the anterior pituitary gland to release FSH and LH.

FSH (Follicle Stimulating Hormone)

A hormone that stimulates the growth of ovarian follicles and the secretion of oestrogen.

LH (Luteinizing Hormone)

A hormone that triggers ovulation and the formation of the corpus luteum.

Graafian follicle

A mature ovarian follicle that is ready for ovulation, containing a secondary oocyte.

Menopause

The time in a woman's life when menstruation ceases completely, typically occurring between ages 46 to 64.

Mammary glands

Modified sweat glands that are responsible for the synthesis, secretion, and ejection of milk.

Vagina

A 10 cm long fibro-muscular canal extending from the cervix to the external body, serving multiple reproductive functions which are a receptacle for the penis, outlet for menstrual flow and a passage-way for childbirth

Myometrium

The middle layer of the uterus composed of smooth muscle that contracts during labor to expel the fetus.

Oestrogen

The primary female sex hormone, secreted by the ovaries, crucial for the thickening of the endometrium and female sexual characteristics.

What are the functions and effects of oestrogen?

• endometrial thickening and development of glands

• increases vascularisation of myometrium and endometrium

• development of ducts in breasts and breast enlargement

• maintains female secondary sex characteristics

• increases protein anabolism including building strong bones

• lowers total blood cholesterol level, protecting from cardiovascular disease

Progesterone

A hormone secreted by the corpus luteum that prepares the endometrium for potential pregnancy after ovulation.

Hormonal feedback loop

Process by which hormonal levels regulate the release of other hormones, ensuring balance in the reproductive cycle.

Phases of the female reproductive cycle

In order:

Menstrual phase, pre-ovulatory phase, ovulation, post-ovulatory phase

1. Menstrual Phase

What days and outline

days 1 to 5, where the uterine lining is shed and menstrual bleeding occurs. Low progesterone causes spiral arterioles to constrict so lack of blood supply causes functional layer endometrium to die. This detaches from the uterine wall and is shed.

2. Pre-ovulatory phase

Days and outline

days 6 to 13, where the endometrium begins to thicken in preparation for a potential pregnancy. Follicle-stimulating hormone (FSH) promotes the growth of ovarian follicles which secretes estrogen so levels rise. A dominant follicle matures into a mature follicle which bulges at the surface of the ovary. In the uterus this phase involves the regeneration of the endometrial lining, spiral arterioles grow back - called proliferative phase.

3. Ovulation

Days and outline

This phase occurs around day 14 of the cycle when a mature (Graafian) follicle releases a secondary oocyte into the abdominopelvic cavity. A surge in LH triggers this process, marking the transition to the next phase, and the egg is available for fertilization.

Signs of Ovulation

Increased basal body temperature, cervical mucus thins to allow sperm through - caused by increased oestrogen, cervix softens, discomfort/pain.

Following Ovulation

• the ovarian follicle collapses

• so the follicular cells begin to enlarge and change to form the corpus luteum - caused by LH

• the corpus luteum secretes progesterone and oestrogen.

4. Post-ovulatory phase

Days and outline

Days 15-28 between ovulation and next period. In ovary the corpus luteum secretes progesterone and oestrogen, if the ovum is not fertilized the corpus luteum becomes a corpus albicans.

in the uterus progesterone and oestrogen promote thickening of endometrium which becomes highly vascular and glandular if there is an embryo otherwise next menstrual phase will begin.

Functions and effects of progesterone

• stimulates development of secretory tissue in the thickened endometrium

• vascularisation of the myometrium and endometrium

• development of glandular tissue in breasts

2 menstrual disorder and what they are

Dysmenorrhea = pain/discomfort associated with menstruation that is not pathologically explicable. It may show high levels of prostaglandins so treatment is medications that block prostaglandins.

Amenorrhea = absence of menstruation usually by pregnancy or menopause or very low body fat. Results in menstrual cycle ceasing and loss of bone mass and oestrogen levels decrease.

The combined oral contraceptive pill

Combined oestrogen and progesterone that work a negative feedback mechanism on the anterior pituitary gland blocking FSH and LH, inhibiting ovulation and development of the follicle.

Benefits are that it combats irregular, painful or heavy periods.

The main complication is thromboembolism and other cardiovascular risks, especially in smokers.

The 2 hormone controlled contraceptives

Mirena = hormonal IUD that releases a hormone similar to progesterone in low doses, preventing growth of endometrium and thickening the cervical mucus.

Jadelle = inserted under the skin in the upper arm, slow-release progesterone that prevents ovulation and thickens cervical mucus.

Menarche is …

the first occurrence of menstruation in a female

Consequences of low oestrogen

• reproductive and breast tissue atrophy

• dry vagina

• weight gain

• loss of bone mass

• rising blood cholesterol but decreased HDL

• hot flushes and sweating

• some women experience irritability and depression or mood changes

Structure and functions of the uterus

The uterus is a muscular organ located in the female pelvis, responsible for housing and nurturing the developing fetus during pregnancy. It has 3 layers - endometrium, myometrium and perimetrium.

Its functions are a route for sperm, receives, retains and nourishes the fertilised ovum and the myometrium muscles expel the fetus during labour.

Location and functions of the cervix

It is the narrow neck of the uterus

It produces cervical mucus, allows passage during labour, and protects the uterus from bacteria etc.

Cervical cancer

A type of cancer that occurs in the cervix, often caused by persistent infection with human papillomavirus (HPV). It can lead to abnormal cell growth and, if untreated, may progress to invasive cancer.

Gardasil vaccine and cervical smears help prevent it.

Vulva …

mons pubis - fat pad that cushions pubis symphasis

labia majora - outer folds

clitoris - erectile tissue that has a role in sexual excitement

labia minora - inner folds

vestibule - area between labia minora

Breast cancer

Happens in epithelial cells of ducts.

Risk factors include early menses and late menopause, no pregnancies or breastfeeding and family history.

Diagnosis - change in skin texture, skin puckering, leakage from nipples, mammogram detects it.

Oxytocin

On a positive feedback loop so the more the baby feeds the more it stimulates the release of oxytocin, which promotes milk ejection and strengthens uterine contractions during labor.

Pathway of sperm to the oocyte

Vagina → cervix → uterus → fallopian tube ampulla where fertilization occurs.

Metabolism

Refers to all the chemical reactions in the body.

Anabolism

The process of building up larger molecules from smaller ones.

Catabolism

The process of breaking down larger molecules into smaller ones.

Glycogenesis

The process of glucose storage where excess glucose molecules are joined together to form glycogen.

Glycogen

Stored mostly in skeletal muscle fibres and some in liver cells.

Glycogenolysis

The process where glycogen stored in the liver is broken up to release glucose into the bloodstream.

Gluconeogenesis

The process where the liver makes glucose from lipids (from glycerol in triglycerides) and proteins (amino acids) when glycogen stores are used up.

Lipid catabolism

The breakdown of fats, which are the most concentrated store of energy, yielding approximately twice the energy as glucose or protein breakdown.

Lipolysis

The breakdown (catabolism) of triglycerides into glycerol and fatty acids.

Glycerol

Converted into pyruvate (pyruvic acid) and enters the Krebs cycle to produce ATP or can be converted to glucose by gluconeogenesis.

Fatty acids

Converted into acetyl coenzyme A (CoA) in the liver, which then enters the Krebs cycle to form ATP.

Ketone bodies

Produced when the levels of CoA (from gluconeogenesis of proteins) are too high for the Krebs cycle to process.

Lipogenesis

The process where more calories are consumed than are needed, resulting in glucose and amino acids being made into lipids by liver cells and adipose tissue.

Protein metabolism

Amino acids cannot be stored, so a regular intake is required to synthesize new proteins to build or repair body tissues.

Triglycerides

The main lipids used to supply energy.

ATP

Adenosine triphosphate, the energy currency of the cell.

Krebs cycle

A series of chemical reactions used by all aerobic organisms to generate energy.

Excess amino acids

Used for energy production or converted into other compounds.

Clinical significance of ketone bodies

Indicates the state of metabolism, particularly in conditions like diabetes.

Urea

A waste product formed from the breakdown of proteins.

Factors influencing metabolic rate

Includes age, sex, muscle mass, and physical activity levels.

Excess amino acids

Broken down by the liver and used for production of ATP, converted into glucose (gluconeogenesis) and triglycerides (lipogenesis).

Ketone bodies

Produced in small quantities and can be used as fuel; overproduction occurs in severe starvation and uncontrolled diabetes.

Toxicity of ketones

High levels of ketones are toxic, especially to the brain. They are acidic and cause ketoacidosis.

Excretion of excess ketones

Occurs through the lungs, giving the breath a characteristic sweet smell of acetone, and through the urine (ketonuria).

Clinical significance of ketone bodies

Excess production can lower blood pH and cause metabolic acidosis (ketoacidosis).

Amino acid catabolism

The process of breaking down unwanted amino acids

Conversion of ammonia

The liver converts ammonia (highly toxic) to urea, which is excreted in the urine.

Clinical significance of urea

Elevated levels of urea and creatinine in urine indicate decreased renal function.

Metabolic Rate

The rate at which energy is produced during cellular respiration.

Basal metabolic rate (BMR)

The metabolic rate measured under resting/fasting conditions.

Thyroxine

A hormone that increases BMR by stimulating cell respiration, leading to more oxygen use and ATP production.

Factors affecting metabolic rate

Age, gender, body size, pregnancy, eating a meal, physical activity, fever, starvation, and emotional stress can all affect metabolic rate.

Exercise and metabolic rate

Exercise can increase metabolic rate by as much as 15 times.

Hormones affecting BMR

Thyroxine, insulin, growth hormone, testosterone, and the sympathetic nervous system's release of epinephrine and norepinephrine increase BMR.

Body temperature and BMR

Higher body temperature raises BMR.

Food ingestion and BMR

Ingestion of food raises BMR by 10-20%.

Children's BMR

Children's BMR is double that of an elderly person.