BIOl21 Final

Lymphatic system consists of:

Lymph, Lymphatic vessels, lymphoid tissues & organs

Lymph

Fluid that bathes all cells of the body

Lymphatic vessels

Vessels through which the lymph fluid flows and which are studded with lymph nodes (filters lymph fluid)

Lymphoid tissues & organs

Tonsils, adenoids, spleen, and thymus

Lymphatic system

Absorb & return excess interstitial fluid to bloodstream

Lymphatic capillaries absorb fat from small intestine & transport it to bloodstream

Produces, maintains, & distributes lymphocytes

Defends against pathogens/disease

Primary organs in the Lymphatic system

Thymus gland and Bone marrow

Tonsils

Defend against bacteria and other foreign agents

Right lymphatic duct

Drains right upper portion of the body

Thymus Gland

Site where certain white blood cells acquire means to chemically recognize specific foreign invaders

Thoracic duct

Drains most of the body

Spleen

Major site of anitbody production; disposal site for old red blood cells and foreign debris; site of red blood cell formation in the embryo

Some lymph vessels

Return excess interstitial fluid and reclaimable solutes to the blood

Some lymph nodes

Filter bacteria and many other agents of disease from lymph

Bone marrow

Marrow in some bones is production site for infection-fighting blood cells (as well as red blood cells and platelets)

Secondary organs in lymphatic system

Tonsils, spleen, some lymph nodes

Immunity

Body’s ability to defend itself against infectious agents, foreign cells and even abnormally body cells

Types of immunity

1\.) Physical and chemical barriers (Non-specific)

2\.) General Defenses (Non-specific)

3\.) Specific Defenses (Specialized)

Physical and Chemical Barriers - Skin and mucous membranes

Tears, skin, large intestine, salvia, respiratory tract, stomach, bladder

Tears

Wash away irritating substances and microbes

Lysozyme kills many bacteria

Skin

Provides a physical barrier to the entrance of microbes

AcidicpH discourages the growth of organisms

Sweat, oil, and fatty acid secretions kill many bacteria

Large intestine

Normal bacterial inhabitants keep invaders in check

Saliva

Washes microbes from teeth and mucous membranes of mouth

Respiratory tract

Mucus traps organisms

Cilia sweep away trapped organisms

Stomach

Acid skills organisms

Bladder

Urine washes microbes from urethra

General defenses - Second line of defenses

Defensive cells & proteins

Fever

Inflammation

Phagocytes

General defenses: Complement system

Activated complement proteins from complexes of proteins that create holes in the bacterial cell wall

Water and salts diffuse into the bacterium through the holes

Bacterium swells and eventually bursts

Other general defenses

Fever and inflammatory response

General defenses: phagocytes

Neutrophils and macrophages

Specific defenses: Immune system

If a pathogen elicits a very specific response by the body it is called Antigen

Two ways to battle antigens

1\.) Produce antibodies

2\.) Kill the pathogens outright

Each defense using a different type of lymphocyte

Self (MHC) Marker

Labels the body’s cell as “self” or “friends”

Antigen

Molecule often on the surface of a pathogen that immune system recognizes as “nonself” or “foe”

B Lymphocytes

Mature in bone marrow (remember ‘B’ for bone)

Secrete antibodies to neutralize the antigen

Memory B cells (long-term immunity)

How antibodies work?

When antibodies encounter a pathogen with the right surface anitgen, they bind to it, forming an antigen-antibody complex

Some antibodies cause pathogens to agglutinate (clump together)

Formation of antibody antigen complex marks the pathogen for attack by phagocytes or complement proteins

T lymphocytes

Mature in thymus (remember ‘T’ for thymus)

Do NOT secrete antibodies; attack DIRECTLY

Helper T cells enhance the response of other immune cells

Cytotoxic T cells attack and destroy

Reproductive system produces Gametes

\
Male: Sperm

Females: Egg (ovum)

Reproductive organs = gonads

Male: Testes

Females: Ovaries

Reproductive system functions

Produce, protect, and nourish gametes

Trigger puberty

Maintain reproductive ability

Stimulate secondary sex characteristics

Produce hormones involved in sexual maturation and general homeostasis

Gonads

Produce gametes

Ducts

Transport gametes and fertilized eggs

Accessory glands

Facilitate gamete production and survival

Supporting structures

Help deliver and support the gametes

Male reproductive system function

Produce, store, and deliver sperm to female reproductive system

Testes

Produce sperm

Scrotum

Regulates temperature

Epididymis

Stores sperm while maturing

Ductus (vas) deferens

Stores & tranpsport sperm

Ejaculatory duct

Transports sperm and secretions

Penis

Delivers sperm

Seminal vesicles

Secretes fructose, seminal fluid

Prostate gland

Secretes milky alkaline fluid

Bulbourethral gland

Secretes lubricating mucus, cleanses urethra

Testosterone

Controls growth and function of male reproductive tissues

Stimulates aggression and sexual behavior

Secondary Sexual characteristics

LH

Stimulates productive of testosterone

FSH

Indirectly stimulates sperm formation

Female external reproductive organs

Urethra

Clitoris

Labium minora

Labium majora

Female internal reproductive organs

Oviduct

Fimbriae

Ovary

Uterus

Cervix

Vagina

Ovaries

Oocytes (immature eggs)

Secrete estrogen & progesterone

Uterus

Fertilized egg grows

Endometrium & myometrium

Vagina

Labia majora and minora

Clitoris

Female hormonal cycles - Ovarian

GnRH → FSH increase → Ovarian follicle develops

Follicle secretes estrogen - builds up endometrium

High estrogen → LH → ovulation (egg released)

Corpus luteum secretes estrogen and progesterone (affects lining of uterus)

Progesterone production stops → hormone levels decline → menstruation → cycles starts again

Female Hormonal cycles - Uterine

Menstrual: Days 1-5

Proliferative: Days 6-13

Ovulation: Day 14

Secretory: Days 15-28

Early embryonic phase

Ovum is fertilized by sperm

Implants in uterus

2 weeks

Embryonic phase

Weeks 3 thru 8

Fetal phase

Weeks 9 thru birth

Fertilization

Sperm released into female reproductive tract

Travel to oviduct (fallopian tubes)

Fertilization: when sperm and egg unite to form zygote

Fertilization is when the human egg or ovum is released from the ovary, while ovulation is the fusion of sperm and egg

False

Cleavage

Repeated cell division

Differentiation

Causes a cell to become specialized

Morphogenesis

Formation of organs and tissues during development

Morula

Solid mass of stem cells

Blastocyst

Hollow ball of cells

The solid mass of cells that forms through cleavage is called?

Morula

Blastocyst implants what

In the uterine endometrium

At what stage is the developing embryo when implantation into the endometrium occurs?

Blastocyst

Embryonic development

Weeks 3 thru 8

Embryonic disc has two cell types (germ layers)

Endoderm - innermost cell layer

Ectoderm - outer cell layer

Third cell type (germ layer)

Mesoderm - middle cell layer

Extra-embryonic development

Formation of

Umbilical cord

Amnion (holds embryo in fluid)

Yolk sac - becomes digestive and respiratory tracts

Chorionic villi - feta placenta

Placenta - large diffusion filter

Allows exchange of nutrients, gases (oxygen and carbon dioxide), antibodies, embryonic wastes, hormones

Toxic substances: HIV, alcohol, recreational drugs, prescription drugs

External genital development

Week 5-8

Embryo looks more human

Arm, legs, hands, feet, face, gonads

Major organs and systems formed - not fully functional

Week 6

Male/female genital development

Y Chromosomes present

Male

It forms testes

Testes secrete hormones (androgens) that form penis & scrotum

No Y chromosome present

Female

If testosterone is absent female organs form

Fetal stage

Begins the 9th week after conception

Nutrients and waste diffuse down concentration gradient between fetus and mother

38 Weeks - ready for birth

Androgen: Male sex hormones

Testosterone

DHT (Dihydrotestosterone)

Testosterone

Functions in sperm development secondary sex characteristics

Also precursor to DHT

DHT

Triggers the development of male genitals (scrotum & penis)

Androgen Insensitivity syndrom

XY chromosome

Body produces androgens (testosterone) but can’t lock on to cells

So if the body can’t use the androgens the genital and secondary sex characteristics won’t develop

Breast development, vagina

No cervix or uterus

5-Alpha reductase deficiency

XY male

Defect in enzyme that converts testosterone to DHT

Body only produces (and uses) testosterone but not DHT

Because testosterone specifies testes, these individuals have testes (and secondary sex characteristics associated w/ testosterone)

But because DHT specifics the penis and scrotum, these intersexed individuals do not have penis or scrotum

DNA - Deoxygenribonucleic acid

Made of repeating units called nucleotides which are composed of one sugar (deoxyribose), one phosphate, and one nitrogenous base

Nitrogenous base of DNA

Adenine, Thymine, Cytosine, Guanine

Chromosomes

Located in Eukaryotic nucleus

Combination of DNA molecule and specialized proteins called histones

Contain genes: specific segment of DNA that directs the synthesis of a protein

\# of somatic cells chromostomes

46 Chromosomes

23 from each parent (diploid)

Mitosis

Results in identical somatic (body) cells and occurs during growth and repair (diploid)

Meiosis

Gives rise to gametes that have half the number of chromosomes as original cell (haploid)

Interphase

DNA replicates (copies)

Mitosis & Meiosis

Division of nuclear material (DNA)

Cytokinesis

Division of cell to form two identical daughter cells

Mitosis (PPMAT)

Prophase

Prometaphase

Metaphase

Anaphase

Telophase