Overview of Skeletal, Muscular, and Reproductive Systems

Hydrostatic skeleton

Fluid-filled sacs with muscles, found in worms.

Exoskeleton

External skeleton made of chitin in arthropods.

Endoskeleton

Internal skeleton found in Echinodermata and Chordates.

Human skeleton functions

Support, movement, protection, mineral storage, blood production.

Osteoblast

Bone cell that secretes the matrix.

Osteoclast

Bone cell that digests matrix for minerals.

Osteocyte

Mature bone cell maintaining bone tissue.

Bone matrix

Solid structure of molecules surrounding bone cells.

Spongy tissue

Bone tissue with irregular pattern and red marrow.

Compact tissue

Strong bone tissue arranged in osteons.

Articular cartilage

Cushions bone ends, absorbs shock.

Periosteum

Membrane surrounding entire bone for growth.

Medullary cavity

Hollow space containing yellow marrow (fat).

Bone development

Begins at 6-7 weeks of fetal development.

Metaphysis

Cartilage area for bone length growth.

Bone growth hormones

Growth hormone and insulin stimulate growth.

Osteoporosis

Decreased bone density due to low estrogen.

Nutritional needs for bones

Calcium, phosphorus, magnesium, vitamins D and C.

Articulations

Points of contact between two bones.

Synovial joint

Freely movable joint with synovial fluid.

Ligaments

Tissues that connect and hold bones together.

Tendons

Tissues that connect muscles to bones.

Muscle types in humans

Skeletal, cardiac, and smooth muscles.

Myofibrils

Proteins in muscle cells responsible for contraction.

Neuromuscular Junction

Connection between nerve and muscle with synaptic cleft.

Acetylcholine (Ach)

Neurotransmitter that stimulates muscle contraction.

Sliding Filament Mechanism

Theory explaining muscle contraction and relaxation.

Contraction Process

Impulse triggers acetylcholine release and calcium binding.

Relaxation Process

Impulse cessation leads to muscle stretching and detachment.

Asexual Reproduction

One parent produces identical offspring.

Mitosis

Cell division resulting in two identical cells.

Budding

Miniature form grows on parent, detaches to form new.

Regeneration

Body fragments grow new parts to form new organism.

Fission

Organism divides in half to create new organisms.

Parthenogenesis

Haploid cells develop into haploid organisms.

Sexual Reproduction

Two parents produce varied offspring through meiosis.

Monecious

Organisms with both male and female reproductive organs.

Diecious

Organisms with separate male and female bodies.

External Fertilization

Sperm and egg fuse outside the parent's body.

Amplexus

Male frog behavior to stimulate egg release.

Internal Fertilization

Sperm fusion occurs inside the female body.

Copulation

Male inserts penis into female for fertilization.

Spermatophore

Sperm package transferred from male to female.

Haploid Cells

Cells with half the number of chromosomes.

Spermatogenesis

Sperm production process starting at puberty.

Sperm Structure

Head, midpiece, and tail enable egg penetration.

Sperm Lifespan

Sperm survive up to 48 hours post-ejaculation.

Sperm Pathway

Sequence from seminiferous tubules to urethra.

Seminiferous Tubules

Site of sperm production in testes.

Epididymis

Stores sperm for up to 1 month.

Vas Deferens

Transports sperm via peristalsis.

Ejaculatory Duct

Where sperm mixes with gland secretions.

Semen

Mixture of sperm and gland secretions.

Semen pH

Ranges from 7.2 to 7.6.

Average Ejaculation Volume

2.5 - 5.0 ml of semen.

Sperm Concentration

50 - 150 million sperm per ml.

Semen Clumping

Sperm clump post-ejaculation, dissolving in 5-20 minutes.

Seminal Vesicles

Produce fructose, fibrinogen, prostaglandins, and alkaline fluid.

Prostate Gland

Secretes fibrinolysin to break sperm clumps.

Bulbourethral Gland

Produces mucus for lubrication and neutralization.

Semen Analysis

Tests male fertility; <20 million sperm/ml is infertile.

Erection Reflex

Parasympathetic response causing penile blood flow.

Ejaculation Reflex

Sympathetic response propelling semen from urethra.

Oocyte

Female gamete produced in ovaries.

Oogenesis

Process of egg production in females.

Primary Oocyte

Diploid cell halted in meiosis.

Menstrual Cycle

28-day cycle preparing for potential pregnancy.

Menstrual Phase

Days 1-5; shedding of endometrial tissue.

Preovulatory Phase

Days 6-13; follicle maturation and estrogen increase.

Ovulatory Phase

Day 14; release of oocyte from follicle.

Postovulatory Phase

Days 15-28; corpus luteum secretes hormones.

Fertilization

Fusion of sperm and oocyte in fallopian tube.

Acrosome Reaction

Sperm digests oocyte's outer wall for fertilization.

Acrosome

Structure that helps sperm penetrate oocyte.

Syngamy

Fusion of sperm and oocyte nuclei.

Zygote

First diploid cell formed after fertilization.

Blastula

Early embryonic stage formed by rapid mitosis.

Implantation

Blastula attaches to the endometrium.

hCG

Hormone maintaining corpus luteum during pregnancy.

Chromosomes

46 total, 23 from sperm, 23 from oocyte.

Sex Chromosomes

23rd pair determining biological gender.

Identical Twins

Result from one zygote splitting into two.

Fraternal Twins

Develop from multiple fertilized oocytes.

Amnion

Membrane forming sac around the embryo.

Amniotic Fluid

Fluid providing support and moisture to embryo.

Yolk Sac

Part of embryo's gut development.

Allantois

Forms umbilical cord for nutrient exchange.

Chorion

Outer membrane developing into the placenta.

Labor

Process of expelling fetus from uterus.

Oxytocin

Hormone increasing during labor for contractions.

Dilation Stage

Initial labor stage with contractions and amniotic rupture.

Expulsion Stage

Stage of labor involving delivery of baby.

Placental Stage

Final stage of labor with placenta expulsion.

Lactation

Milk production by mammary glands post-delivery.

Colostrum

First milk rich in nutrients and antibodies.

Endocrine System

Glands producing hormones for homeostasis.

Tropin

Hormone stimulating another endocrine gland.

Pituitary Gland

Master gland regulating other endocrine glands.

Permissive effect

One hormone enhances another's action.

Synergistic effect

Multiple hormones work together for a greater effect.