all first semester of anatomy

skeletal muscle

voluntary, multi-nucleated striated muscle that allows movement, maintains posture, stabilizes joints and generates body heat

myo

prefix meaning 'muscle'

sarco

prefix meaning 'flesh', indicates the word is related to muscle

basic jobs of all muscles

contract and relax

tendon

cord-like extension of the epimysium made of dense connective tissue that attaches to bone, cartilage or other connective tissue

aponeurosis

sheet-like extension of the epimysium made of dense connective tissue that attaches to bone, cartilage or other connective tissue

endomysium

connective tissue surrounding muscle fiber (cell)

perimysium

connective tissue enclosing several muscle fibers to form a fasicle

epimysium

connective tissue wrapping around the many fasciles of an entire muscle

smooth muscle

non-striated muscle that lines the walls of hollow organs such as the digestive tract, lungs, blood vessels and bladder, involuntary

cardiac muscle

striated, involuntary, uninucleate, branching muscle fibers arranged in figure 8 shape which compose the bulk of the walls of the heart

sarcoplasmic reticulum

Organelle of the muscle fiber that stores calcium.

sarcomere

functional and structural unit of muscle contraction

synaptic cleft

a gap between the axon terminal and the muscle cell into which neurotransmitters are released from the axon terminal

motor neuron

one nerve cell and all the skeletal muscles it stimulates

axon terminal

The endpoint of a neuron where neurotransmitters are stored

action potential

a neural impulse; a brief electrical charge that travels down an axon (and into a muscle cell)

actin

thin contractile protein filaments

myosin

thick contractile protein filaments

myosin heads

extensions of myosin filament that bind to specific sites on actin molecules to form cross bridges

Acetylcholine

A neurotransmitter that triggers muscle contraction (and also enables learning and memory)

sliding filament theory

theory of muscle contraction;

sarcomeres shorten when thick filaments pull on thin filaments

Z disc

provides anchorage for thin filaments and elastic filaments

fasicle

bundle of muscle fibers, encased in perimysium

A band

dark band

I band

light band, thin filaments only

H zone

center part of A band where no thin filaments occur, disappears in full contraction

fused tetanus

when stimulus frequency is so high that no muscle relaxation takes place between stimuli

unfused tetanus

some relaxation occurs between contractions

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

creatine phosphate

biochemical molecule that stores energy and can directly phosphorylate ADP

anaerobic glycolysis

the overall process where sugar is split into pyruvic acid to generate 2 ATP and lactic acid (byproduct)

aerobic respiration

cellular respiration that uses oxygen, sequentially releasing energy and storing it in ATP (~32 ATP per glucose)

isotonic contraction

A muscle contraction that pulls on the bones and produces movement of body parts.

isometric contraction

Muscle contracts but there is no movement, muscle stays the same length

extension

Straightening of a joint

flexion

Decreases the angle of a joint

rotation

movement of a bone around its longitudinal axis

abduction

Movement away from the midline of the body

adduction

Movement toward the midline of the body

Dorsiflexion

bending of the foot or the toes upward

plantar flexion

pointing toes

Inversion

Turning the sole of the foot inward

Eversion

turning the sole of the foot outward

Pronation

turning the palm downward

Supination

movement that turns the palm up

opposition

Movement of the thumb to touch the fingertips

troponin

regulatory protein that binds to actin, tropomyosin, and calcium (when contraction is happening). When not contracting troponin is blocked.

Synapse

the junction between the axon terminal of the sending neuron and the muscle, organ or neuron that is receiving the signal

acetylcholinesterase (AChE)

the enzyme that breaks down acetylcholine in the synaptic cleft

Testes

male gonads, produce sperm & hormones (mostly testosterone)

Gonads

Sex organs: ovaries in females, testes in males.

seminiferous tubules

Narrow, coiled tubules that produce sperm in the testes.

rete testis

network of tubules between the seminiferous tubules and the epididymis, concentrate & mix sperm

epididymus

structure in the male reproductive system in which sperm are fully matured and are stored (can be 6m long!)

vas deferens

tube that carries sperm from the epididymis to the urethra

bulbourethral glands

the two glands below the prostate that secrete a sticky fluid that becomes a component of semen

prostate

a gland surrounding the neck of the bladder in male mammals and releasing prostatic fluid.

seminal vesicles

two small glands that secrete a fluid rich in sugar that nourishes and helps sperm move

Urethra

tube leading from the urinary bladder to the outside of the body

glans

head of the penis

prepuce

foreskin; loose casing that covers the glans penis; removed by circumcision

Scrotum

a pouch of skin containing the testicles.

tunica albuginea

white fibrous capsule on testes

urinary bladder

muscular sac in the pelvis that stores and releases urine through the urethra

Testosterone

the most important of the male sex hormones. Both males and females have it, but the additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty

interstitial cells

small specialized cells in the testes (near the seminiferous tubules) that secrete the male sex hormone, testosterone

Sperm

the male gametes (reproductive cells)

acrosome

A region at the head of a sperm cell that contains digestive enzymes to help the sperm penetrate into the oocyte (within B on the diagram)

midpiece of sperm

generates ATP from fructose and contains many mitochondria (C on the diagram)

Flagellum

A long, hairlike structure that grows out of a cell and enables the cell to move. (D on the diagram)

Spermatogenesis

production of sperm

Spermiogenesis

transformation of spermatids to spermatozoa during spermatogenesis

secondary sex characteristics

male voice quality, body hair, enlargement of muscles, increased bone density

vasectomy

ligation of a segment of the vas deferens to produce sterility in the male

Hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

Gonadotropin-releasing hormone (GnRH)

A hormone released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH.

Mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

spermatogonia

Stem cells in a testis that can give rise to primary spermatocytes.

lumen

space within a tubular part or organ, such as the space within the seminiferous tubules (6 on this diagram)

spermatid

an immature male sex cell formed from a spermatocyte that can develop into a spermatozoan without further division.

erectile tissue

Specialized tissue with a lot of space that can fill with blood upon proper stimulation, causing the tissue to become firm. Found in the penis, the clitoris, the labia, and the nipples.

pregnancy

events that occur in a woman's body from the time of fertilization (conception) until delivery (birth)

gestation

the first day of the last menstrual period until birth (~280 days), time during which development occurs

fertilization

the moment the genetic material of the sperm and ovum combine

zygote

fertilized egg, 1 cell, 46 chromosomes

cleavage

the process when a single cell (zygote) rapidly divides into smaller cells as it travels to uterus

embryo

stage of development from fertilization —> 8 weeks

morula

a cluster of 16 cells that arrive in uterus, float free, and use uterine secretion for nutrition

blastocyst

~100 cells, hollow, ball like, secretes human chorionic gonadotropin (hCG) to signal corpus luteum to continue making hormones (to prevent sloughing off endometrium)

human chorionic gonadotropin (hCG)

hormone secreted by a blastocyst that signals the corpus luteum to continue making hormones so the endometrium will not be shed

placenta

temporary endocrine organ that makes estrogens, progesterone, relaxin and other hormones for pregnancy, provides nutrients and oxygen to the developing fetus, and carries away waste

amnion

fluid sac that surrounds the embryonic body, attaches to placenta via umbilical cord

umbilical cord

a structure containing arteries and veins connecting the fetus and the placenta

fetus

stage of development from 9 weeks to infant

relaxin

hormone secreted by the placenta that causes ligaments and pubic symphysis to relax and widen (helps with birth, may cause waddle)

abortion

medical termination of a pregnancy

labor

series of events that expel the infant from the uterus

oxytocin

a hormone released by the posterior pituitary gland that causes increased contraction of the uterus during labor and stimulates the ejection of milk into the ducts of the breasts