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Junction Types - Tight and Adherens Junctions

By: HWC, Views: 8055

Many tissues contain in tercellular junctions between cells. 1. Tight junction 2. Adherens junction 3. Desmosome 4. Hemidesrnosome 5. Gap junction 1. Tight junction • Web-like strips of proteins fuse together adjacent plasma membranes. • Tight junctions prevent the transport...

Type of Cell Junctions - Desmosome, Hemidesmosomes and Gap Junctions

By: HWC, Views: 8092

Cell Junctions: Cell junctions are found in some multi-cellular organisms. They exist of complexes and are found between cells and between cells and other structures. The junctions provide a way for cells to connect and exchange signals. What are tight junctions, desmosomes, and gap junctions...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 7897

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...

Contraction cycle of a sarcomere

By: HWC, Views: 8203

• A single nervous signal releases Ca2+ ions into the sarcoplasm and initiates the contraction cycle. step 1. ATP hydrolysis • ATP provides the to move myosin molecules back into the energized configuration necessary to perform the power stroke. Step 2. Crossbridge attachment • Myosin...

Nervous pathway to the Neuromuscular (NMJ)

By: HWC, Views: 8292

• A nervous impulse, also called an action potential, starts from the brain or spinal cord to signal skeletal muscle cell contraction. Action potentials continue along a motor neuron to the muscle cell. • The signal to contract must cross a synapse - the neuromuscular junction (NMJ) - betwe...

Hormonal regulation of pregnancy - week 1

By: HWC, Views: 8051

• During pregnancy, hormones play a significant role in triggering changes in the mother and fetus. • Ormones : • Maintain the lining of the uterus and prevent menstruation. Prepare the mammary glands for lactation. • Increase flexibility of the pubic symphysis. • Affect the mot...

Hormonal regulation of pregnancy - weeks 2 through 38

By: HWC, Views: 8176

Weeks 2 through 16 • During the first few months of pregnancy, estrogen and progesterone are secreted primarily by the corpus luteum. • These hormones act to maintain nutritional support for the embryo and fetus. • hCG production increases, peaking at 8 weeks. • hCG triggers the c...

Hormonal regulation of pregnancy - weeks 17 through 38

By: HWC, Views: 7999

• Estrogens increase uterine blood flow, maintaining the endometrium during pregnancy. • High levels of estrogen and progesterone inhibit the synthesis of milk. Progesterone inhibits myometrial contractions of the uterus to prevent premature birth. • Relaxin inhibits myometrial contract...

Lactation and Breast Feeding

By: HWC, Views: 8550

Regulation of lactation - breast preparation • Pregnancy hormones trigger breast changes to prepare for feeding the new baby. • The amount of the hormone prolactin, essential to the initiation of lactation, increases steadily throughout pregnancy. • However, high levels of both estroge...