Three nutrition guidelines are they have to be based on a 2,000 calorie diet 2. fruits and vegetables.3. and the food pyramid. based.
Answer:
1. spontaneously
2. resting potential
3. action potentials
4. pacemaker potentials
5. K+
6. Na+
7. into
8. Ca+
Explanation:
Pacemaker cells (also known as sinoatrial node cells) are cells that generate rhythmic impulses and set the pace for blood pumping in the heart. These cells have the ability to rhythmically depolarize and initiate action potentials. In pacemaker cells, Ca2+ and Na+ levels are higher in the extracellular environment, while K+ concentration is higher intracellularly. The pacemaker action potentials have three phases: 1-depolarization, where membrane potential reaches -40 mV and voltage-gated Ca2+ channels open, 2-repolarization, where voltage-gated Ca2+ channels close and voltage-gated K+ channels open, and finally 3-gradual depolarization, which is caused by the slow influx of Na+ ions.
Answer:
True
Explanation:
This information is a great reminder of how important we are in each other's lives. We all need to make the time to get out and see our friends and family. Especially because face-to-face socialization goes beyond depression, reducing stress and anxiety as well. We all benefit from strong, healthy relationships.
Answer:
The hip joint is a ball-and-socket joint that allows motion and gives stability needed to bear body weight.
Explanation:
Answer:
Explanation:
Bone formation, also called ossification, process by which new bone is produced. Ossification begins about the third month of fetal life in humans and is completed by late adolescence. The process takes two general forms, one for compact bone, which makes up roughly 80 percent of the skeleton, and the other for cancellous bone, including parts of the skull, the shoulder blades, and the ends of the long bones.
Bone of the first type begins in the embryonic skeleton with a cartilage model, which is gradually replaced by bone. Specialized connective tissue cells called osteoblasts secrete a matrix material called osteoid, a gelatinous substance made up of collagen, a fibrous protein, and mucopolysaccharide, an organic glue. Soon after the osteoid is laid down, inorganic salts are deposited in it to form the hardened material recognized as mineralized bone. The cartilage cells die out and are replaced by osteoblasts clustered in ossification centres. Bone formation proceeds outward from these centres. This replacement of cartilage by bone is known as endochondral ossification. Most short bones have a single ossification centre near the middle of the bone; long bones of the arms and legs typically have three, one at the centre of the bone and one at each end. Ossification of long bones proceeds until only a thin strip of cartilage remains at either end; this cartilage, called the epiphyseal plate, persists until the bone reaches its full adult length and is then replaced with bone.
The flat bones of the skull are not preformed in cartilage like compact bone but begin as fibrous membranes consisting largely of collagen and blood vessels. Osteoblasts secrete the osteoid into this membrane to form a sponge like network of bony processes called trabeculae. The new bone formation radiates outward from ossification centres in the membrane. This process is called intramembranous ossification. There are several ossification centres in the skull. At birth, bone formation is incomplete, and soft spots can be felt between these centres. The lines where the new bone from adjacent centres meets form cranial sutures visible on the surface of the adult skull.
Both endochondral and intramembranous ossification produce immature bone, which undergoes a process of bone resorption and deposition called bone remodeling to produce mature bone.
