IPHY 3430 Exam 1

Zygote

When egg and sperm meet (1 sperm + 1 oocyte)

Sex organs

Gonads, internal and external genitalia

Gonads

Produce gamete, undifferentiated gonads when zygote first forms, produce germ cells

Gonads (male)

Testes produce sperm

Gonads (female)

Ovaries produce eggs (ova)

Internal genitalia

Accessory organs and ducts (connect gonads to external environment)

External genitalia

All external reproductive structures

Chromosomes

X comes from female or male (when gametes combine one X will be silenced, inactivation is random), Y comes from male

XX

Female

XY

Male

Bipotential gonad

Can't be classified as male or female, begins to differentiate after 7 weeks

Internal reproductive organs

Two pairs of accessory ducts (Wolffian and Mullerian ducts)

Wolffian ducts

Derived from kidneys, develop into male system

Mullerian ducts

Default, develop into female system

SRY gene

Determining region of Y chromosome, activates other genes, testes differentiate

Developing testes

Release three hormones, anti-mullerian, testosterone, and DHT

Anti-mullerian hormone (AMH)

Secreted by sertoli cells, causes regression/breakdown of mullerian ducts

Testosterone -> DHT

Produces dihydrotestosterone (DHT) = dominant male hormones

Testosterone

Development of internal genitalia, converts wolffian ducts into epididymis, vas deferens, seminal vesicle, helps with later development (migration of testes into scrotum)

DHT

Mainly external genitalia, controls prostate development

Female internal organ development

SRY gene and protein absent, gonadal cortex develops into ovarian tissue, mullerian ducts develop into female organs (vagina, uterus, fallopian tubes), wolffian ducts degenerate

GnRH

Stimulates anterior pituitary, releases luteinizing hormone (LH) and follicle-stimulating hormone (FSH)

LH

Acts on endocrine cells, stimulates production of sex hormones (testosterone, estrogen, progesterone), assist gamete production in females

FSH

Helps gamete production (female and male)

Long loop feedback

GnRH release by hypothalamus, LH and FSH release by anterior pituitary

Short loop feedback

GnRH release by hypothalamus

Spermatogenesis (testis)

Sertoli cells and leydig cells

Sertoli cells (FSH)

Developing sperm at various stages, surround and support developing sperm

Leydig cells (LH)

Produce testosterone

Spermatogenesis (LH) - Leydig cells

Go to sertoli cells, convert T to DHT, accumulate in lumen

Spermatogenesis (FSH) - Sertoli cells

Androgen-binding protein (concentrate T in lumen), inhibin (provides negative feedback onto FSH), enzymes (convert T into DHT, signals spermatogenesis)

Ovarian cycle

Follicular phase, ovulation phase, luteal phase

Follicular phase

Proliferation of granulosa cells, development of antrum, maturation of oocyte

Ovulation phase

Ripened follicle bursts, releasing oocyte (breaks through ovarian wall)

Luteal phase

Ruptured follicle develops into corpus luteum

Uterine cycle

Menses phase, proliferative phase, secretory phase

Menses phase

Occurs if pregnancy isn't achieved, bleeding from uterus as endometrium is shed (during early follicular phase)

Proliferative phase

Endometrium grows in preparation for pregnancy (during late follicular phase)

Secretory phase

Endometrial secretions promote implantation (during luteal phase)

Extra ovarian hormones

GnRH from hypothalamus, LH and FSH from anterior pituitary (LH surge triggers ovulation)

Ovarian hormones

Produces estrogen, progesterone, inhibin, and AMH

Estrogen

Dominant during follicular phase

Progesterone

Dominant during luteal phase

Inhibin

Inhibits secretion of FSH

Erection reflex

Parasympathetic NS innervates vascular system (only in erection reflex) causes arterioles to vasodilate (increase blood flow), sympathetic NS inhibited

Fertilization

Sperm capacitation occurs in vagina (final maturation step, sperm swims "upstream" to oocyte in fallopian tube)

Zona pellucida

Protective glycoprotein layer of oocyte

Acrosomal reaction

Sperm head has many digestive enzymes, dissolves zona pellucida and cell junctions to reach oocyte plasma membrane

Fertilization (1)

Sperm makes contact with egg in fallopian tube

Fertilization (2)

Acrosome reacts with zona pellucida

Fertilization (3)

Acrosome reacts with perivitelline space

Fertilization (4)

Plasma membrane of egg and sperm fuse

Fertilization (5)

Sperm nucleus enters egg, nuclear fusion creates diploid cell

Fertilization (6)

Cortical granules fuse with egg plasma membrane, renders vitelline layer impenetrable to sperm (blocks polyspermy)

Dizygotic twins (fraternal)

Two fertilized eggs, fraternal twins (can be female and male)

Monozygotic twins (identical)

One fertilized egg, divides before implantation (only male or only female)

Early development

Rapid cell divisions follow fertilization, blastocyst -> implantation

Blastocyst

Hollow ball, ~100 cells, arrive in uterus on day 4 or 5

Implantation

Blastocyst invades endometrium

Placenta, continuing development

Hormones, hCG, estrogen, progesterone

Human chorionic gonadotropin (hCG)

"Rescue" of corpus luteum

Estrogen/Progesterone (development)

Critical for maintaining pregnancy and for normal development

Parturition

Birth process, about 40 weeks, prior to labor, softening of cervix, placental release and expulsion

Labor

Rhythmic uterine contractions, positive feedback cycle of oxytocin release, cervical dilation

Which of the following is a teleological answer for the following: Why do the lungs expand during inspiration?

A. Because contraction of the diaphragm causes thoracic cavity volume to increase.

B. Because air needs to be brought into the lungs for gas exchange.

C. Because the pressure in the atmosphere exceeds thoracic pressure.

B - Because A and C tell you more of a mechanistic approach and they are not telling why. B tells us why - "I need the air for the gas exchange"

Physiology

Study of functions and processes of living organisms

Pathophysiology

Study of physiology gone awry

Themes in physiology

Homeostasis and control systems, structure-function relationships, compartmentation, and energy transformation within biological systems

What is the unit of life?

The cell

4 types of tissue

Epithelial, connective, muscle, nervous

Teleological Approach

Explains "why" (function/purpose)

Mechanistic approach

Describes "how" (process or mechanism)

Homeostasis

"Similar condition"; balancing act; affected by external or internal change; physiological attempt to correct; controlled by feedback loops; ex: body temperature, blood pressure, blood glucose

Physical requirements for membrane transport

Molecular size, solubility in lipids, and ionic charge/polarity

Energy requirements for membrane transport

Concentration gradient and ATP (direct or indirect)

What are the passive membrane transport processes?

Simple diffusion, facilitated diffusion, and osmosis

Simple diffusion

Moving from area of high concentration to area of low concentration

What does facilitated diffusion use/depend on?

Transmembrane proteins which bypass the phospholipids

Types of transmembrane proteins

Channel proteins and carrier proteins

Channel proteins

Continuous opening between intracellular and extracellular fluid

Carrier proteins

Bind to molecules and change shape to shuttle them across the membrane - only open to one side of the membrane at a time

Osmosis

Facilitated diffusion of water; depends on osmolarity, osmotic pressure, and hydrostatic pressure

Aquaporins

Channel proteins which transport water

Osmolarity

Number of particles dissolved in a unit of fluid

Osmotic pressure

Force that controls water entering/leaving a cell; is directly proportional to osmolarity

Water wants to move towards...

Higher osmolarity and higher osmotic pressure in order to create an equilibrium of these 2 factors

Hydrostatic pressure

Pressure exerted by a volume of fluid against a wall, membrane, or some other structure that encloses the fluid

Tonicity

Impact of osmotic pressure on the shape of cells

Hypertonic solution

Solution is very concentrated with solutes so the solution has high osmotic pressure and water is forced out of the cell

Hypotonic solution

Solution is very low in solutes so the osmotic pressure of the cell is high and water is forced into the cell

Which of the substances would be able to readily/easily cross the plasma membrane?

A. Glucose - polar

B. Na+ - polar

C. Water - polar

D. Oxygen - nonpolar

E. Proteins - polar

D. Oxygen - nonpolar

The following substances need to be able to enter into a cell. How will they do so? What will be the mechanism of diffusion? i.e. facilitated (carrier or channel) or simple diffusion. Based on physical requirements.

A. Glucose - polar

B. Na+ - polar

C. Water - polar

D. Oxygen - nonpolar

E. Proteins - polar

A. Facilitated diffusion; carrier protein (bc its too big to have a channel protein)

B. Facilitated diffusion; channel protein

C. Facilitated diffusion; channel protein

*We do not have any active transports for water or any gated transports - all water channels are porous.

D. Simple diffusion (no physical requirement)

E. Facilitated diffusion; either a channel or carrier protein, depends on size

Primary active transport

ATP binds to carrier and is directly used to move molecule

Secondary active transport

Uses concentration gradient which was created through expenditure of ATP

Uniporter

Carries a single substance

Symporter

Carries two substances, moves them in the same direction

Antiporter

Carries two substances, moves them in opposite directions

[Na+] is higher outside of the cell while [K+] is higher on the inside of the cell. The Na+/K+ ATPase is a channel protein that maintains this concentration. What type of carrier protein carries out this function?

A. Symporter

B. Antiporter

C. Uniporter

D. Gated Channel

B. Antiporter

[Na+] is higher outside of the cell while [K+] is higher on the inside of the cell. The Na+/K+ ATPase is a channel protein that maintains this concentration. What is the type of transport based on energy requirements?

A. Facilitated diffusion

B. Primary active transport

C. Secondary active transport

D. Simple diffusion

B. Primary active transport

Distribution of Na+

High concentration in extracellular fluid (plasma and interstitial fluid) and low concentration in intracellular fluid